I have a Lezyne Mega XL, and have put quite a few miles on it. I got the whole package (computer, speed/cadence sensor, HRM and the mounts). The packaging was excellent and so is the computer. I originally had a Windows Phone, so had to set it up after pairing it to my Google tablet. Set up took all of 10 minutes for me and I was ready to go. I love that I can have white numbers on a black background, which makes it incredibly easy to see on a bright day for me. Have no problems reading the screen even using polarized glasses. Have the backlight set to low, and my computer rarely needs charging. I have set it up on a landscape mode, with 9 metrics being displayed. The top row is the current metrics (distance, speed, cadence). The second row contains the average speed, maximum height climbed and current HR. The third row contains average cadence, grade in percent and average HRM (I know, I can be more practical :-)). You can set up multiple screens if you so want. There are other fancy features (read text messages aloud, send tracking crumbs to specified people), which I have not configured. What I liked was the abililty to download maps of any section of the US to the computer, so that you don't have to rely on a connection to your phone for the computer/GPS to work.

My usual 60-70 mile ride is mostly on public roads, so there is very little tree overage when riding. But there is a section about 6 miles where I have to use a MUP which is very heavily wooded. On roads (not surprisingly) and even in the wooded sections, I never lost GPS signal. In fact, if I zoom enough on the maps after the rides, I can clearly distinguish separate to and from tracks of my bike. I have used this on a lot of public rides in lower Westchester, Poughkeepsie, Millerton and Catskill. I usually import the rides from the organizers as a GPX/TCX file and load it from my computer (you can also do it on your mobile, but you have to use a browser and not the app). When I am ready to start my ride (I switched over to Google Pixel phone), I open the app, hit "Go" from the Navigation section, and am usually ready to go with directions loaded from my phone to the cycle computer in under a minute. Any ride, I usually have a GPS lock within 30 seconds of powering on the computer. One thing I haven't really explored is what else could I extract from the downloaded ride data (currently get altitude, speed, cadence, HR and temperature).

I have built and uploaded routes from my computer, but rarely had the need to use routing from my computer (since I am familiar with the areas I bike in), so cannot comment on that. All in all, I would consider the money I spent on this to be worth every penny.