The only failure I've personally witnessed on a good number has been the battery cable wire breakage because you have to pull the battery to charge it. It's relatively easy to fix if a person has even very basic soldering capability. I've read a few of some descriptions of failures and always wonder about the actions of the owner involved but these are fairly rare as far as I've seen.
For shot count in 177, it's quite high if you stay below 20 ft lb and really high if below 12 ft lb.
@Franklink documented a Standard EXTREMELY well a couple of years ago and it's worth the read if you are honestly considering one.
I have ALL the available calibers - 177, 20, 22, 25, and 30 for our 3. 177 was absolutely my own favorite because of firing behavior, shot count, and ammo cost but I just fitted the 20 barrel a month ago and it's been pretty wonderful as well. I use a Heliboard for versatility and convenience, but the GCU2 is just as capable... just doesn't have as many power levels and easy adjustability. Consider that it will shoot near a tin of 8.4s @ 12 ft lb quite accurately, well over 100 shots @ 20 ft lb, and 70ish @ 33 ft lb, all with excellent accuracy...
I've been particularly enjoying the 15 gn NSA's at longer ranges (75 to 200 on my range) and the 20 cal, 18.9s.. The 10.3s, 13.4s, and 16.1s are quite capable at 60 yards and under...
I have a lot of airguns but these are pretty special to me for their versatility, accuracy and firing behavior...
Bob
Edit:
The triggers are light and generally excellent but if you're a true trigger snob, a mechanical trigger will feel better. As has been mentioned, they do not change so are easy to adapt to... My wife's ProTarget is my favorite trigger but the FWB rifles are up there with it...