I upgraded from the 520, I had that for several years and it was stating to show its age, I started to look around at other bike computers but I have been using Garmin since I started riding and have been totally happy with it, so I decided to stay with Garmin and got the 540. very impressed with the screen setup, a little bit of a learning curve with the buttons but figured it out quickly. Love the climbing feature, used it it the other day and it was pretty cool, also like how there's maps pre downloaded, while on my ride I clicked on and showed my location with having to download it. Integrates with my iPhone 16 with no issues. All my sensors quickly connected upon start up. Like the larger screen super easy to read the fields. Overall, very impressed.
I bought the Edge 540 less than a month ago, and I'm very happy with my purchase. My first real bike computer was an Edge 500, then I upgraded to and Edge 820 eight and half years ago. The battery on the 820 was by now lasting less than 3 hours and I needed to recharge the computer at rest stops during long rides LOL!. A friend told me about his 540's battery lasting for several rides and I was sold! The battery on the 540 lasts 26 hours (advertised) in intense mode and this is outstanding for me. The 540 also has a bigger screen than the 820 and it makes it easier to read. I also opted for not having a touchscreen as my experience with the 820's touchscreen was less than ideal in the wintertime while wearing gloves. I was also super pleased with the setup process. I was thinking it was going to take me over an hour to set up my screens and data for my 3 bikes, but this was not the case. The setup process imported all the profiles and screens I had on the 820 and I was ready to ride with my new computer in just a few minutes.