I have the Garmin, and it's the best chrono I"ve ever had or used, and I've had most of them over the years. I had a problem with the first one, and Garmin wasted no time replacing it. I can't say enough good about their customer service.
I shoot from inside my garage a lot and sit near the back with a car parked in the driveway. This would seem to be the worst setup in the world for a radar, and the Garmin never misses a shot.....EVER. I've tried it at 15-20 feet and it works fine. There's just nothing to not like about the Garmin.
I looked into the radars that give bc numbers, but it's kind of a crap shoot. The FX TBC kind of fudges the numbers and you'd be just as well off using a ballistics program and get a bc just as close. I just shoot, get velocity and tune with my ballistics program, done.
I agree $600 is a lot for a chrono, when a light chrono is less than $200 used, but you can set the Garmin up in less than a minute, and shoot at any target you like in the general direction and get velocity, easy peasy. I used to hate setting up my ProChrono, even though it worked every time with lights, but now I use the Garmin a lot.