I'm an amatuer cyclist and spinner and Frontier X user that just switched to X2 and have opted for the Premium Service that includes calculation of V02 Max and VT thresholds. First off, I read the recent negative reviews and I have to say, I've not experienced any problems like those described in the two I read.

However, the reason I went ahead and purchased the X2 was because after 2.5y, my X started having charging issues. I communicated with support and we narrowed the problem down to two causes: a charging cable failure or a device battery/cable connection failure. I was offered the same 30% discount (only 5% above the 25% discount available to every new X2 purchaser).

OK, I get it .....the X2 is expensive but it is an amazing device. I liked every feature of the Frontier X and after studying what is available in X2, I decided to purchase it. After receiving the new boxed X2, I took out the new charging cable and plugged it into my old X device. Boom, it started charging. However, if I wiggled the charging cord connection, the charging stopped and I got a warning on the display to check the charging cord. I carefully re-plugged it to the device and the charging resumed. It's now fully charged. So, I concluded I may have had a charging cord failure (I doubt it because I bought a new one - same problem) and a connection failure on the device (most likely). I think there is a design weakness but it's not fatal. I think the choice of USB A device connectors instead of USB C should be re-evaluated with a redesign of the next X device iteration that features USB C charging cable connectors.

With respect to Frontier taking responsibility for a design weakness in the device charging cable plug, I'd agree with one of the negative reviews that in the case of proven device failures (not operator errors or charging cord failures), that upon contacting support that a pro-rated credit toward the purchase of a new device starting at 50% of the retail price at the expiration of the 1y warranty period, declining to zero % at some point TBD by Frontier (3y?). This way existing customers whose device fails after a year of service or up to 3y, get a reasonable credit towards purchasing a new device and Frontier can incentivise new customers with the % discounts they are using now.

New customers thinking about purchasing the X2 should know this is a high-tech device that allows athletes (or weekend-warriors) to fine tune their training and workouts through buying both the X2 and subscribing to the Premium services. I'd like to see a real time display of V02 max and VT Thresholds during a workout but that is not currently available. However, the after the fact data in the subscription premium service allows the user to structure training events armed with the same kind of information pro-trainers use to train amature and professional runners and cyclists. The ECGs are as close to the real thing as you can get with a single lead sensor (medical ECGs have 12 leads). There is no non-medical comparable device as accurate as the Frontier's X and X2. Given single lead limitations, it is still fully capable of medical interpretation and diagnosis by a qualified MD, but Frontier makes it very clear the device alone being interpreted by untrained users cannot be used for medical diagnosis purposes. The Frontier App in conjunction with the website makes it easy to get PDF copies of an ECG that you can forward to a cardiologist for review and interpretation.

Overall a great product with great tech support. The device works fine when its operation is understood and used according to the available manuals and published FAQs. I'd like Frontier to consider and offer a little better warranty as the devices aren't cheap. I'm looking forward to improving my cycling/spinning performance with the V02 Max and VT data I'm getting post exercise that will guide my training.

For those of us who are aging-athletes with many decades of ultra-endurance training and competition and consequent cardiovascular issues, the metrics FF X2 provides are indispensable to be able to see in real-time. For me, those data, when combined with real-time measurement of muscle oxygen and watt output allow me to calibrate my work to enhance safety and fitness. To my knowledge, there are no other wearable monitors at the price point of the X2 and Premium subscription that can provide such data.

If you want to really learn about your heart health and what impact it, this is the device. Ive used many health devices, and they all more or less give you the same data. While that data is informative, I wanted deeper insights into my heart health and Fourth Frontier does this better than any device I know. Yes, its on the pricier side and I was reluctant about that, but the great thing is that you can get a full, one-on-one demo. I talked with Vijay Kumar who took the time to walk me through what it does, answered all my questions, and made sure the device is a fit for my needs. I was looking for a device that would give me all-day readings, and he showed me exactly how it could do just that. So, the purchase was seamless. I never felt rushed or pressured. The device itself far outdid my expectations. I was nervous about whether the battery would give all-day readings, and it does. The readings give me much better insights into my heart function than any device Ive tried. Whats even better is that you get a consultation with a real healthcare professional who helps you understand your readings. I learned more in that session than months and years of data from other sources and/or doctor visits. Both the mobile device and the desktop dashboard give you a lot of insights. Finally, in just the few months Ive owned this device, they have updated and added features and services so that the device and the information continue to improve. As someone who loves to try out new tech and learn about my health through insights, Im super impressed!

Quick background--I had been having some irregular heart beats during exercise and was looking for a way to investigate what was going on. Found the Fourth Frontier X2 online. I use it every time I workout now and also when I sleep. I have gotten a lot of great insight into my heart health and am quite happy with the product. The X2 is helping me and my doctor manage my newly diagnosed Atrial Fibrillation.
--The Heart Strain indicator is quite helpful. I have had the "buzz" on the device go off a couple of times. It tells me to lower my workout intensity.
--The heart rate is accurate--as compared with my Polar H10 strap and several manual counts. --Breath rate is helpful information not supplied by other heart rate devices --The HRV reading is helpful and compares very close to my Oura ring. --Sleep data is impressive and compares very close to the Oura ring. --The X2 could easily take the place of the Polar H10 strap and Oura ring. --The App is intuitive and provides a lot of useful information. --I love that the app will generate a PDF of the ECG that can be emailed to your cardiologist/doctor. --I love that the X2 is charged via USB instead of a battery like the H10. --Battery life is impressive--I have worn it all night while sleeping followed by 3 hours of use during exercise and have not gone below 70% charge. I once wore it for 18 hours and only got to 60% charge. The X2 charges in just a few minutes-much faster than my Apple watch. --My cardiologist was enthusiastic about my use of the X2. He found the ECG data useful--especially because he could see what was happening during a specific activity. I had worn a 2 week monitor through him--but of course I didn't have any weird beats until after I turned in his device. The X2 ECG is helping to guide my treatment.

I've had lots of exercise monitors over the years but was looking for one with multiple and extensive features. The Fourth Frontier X2 is an excellent monitor providing me with all the stats I'm interested in for a heart monitor...as well as special features such as an indication of VO2 Max (with the premium membership). Also, customer service has been excellent vie email whenever I've had a question.