I have had no issues with the indexing after about 9000 shots. There's a vid on youtube by Steyr on how to re-adjust the barrel, I did this once to try it and it really is a 2 minute job.
Yes, it's quite fussy, My test results are here:
http://www.airgunbbs.com/showthread....-5-pellet-test
(I've just fixed the links as they were aiming at an old server)
It does not have a silencer adapter
If you buy the scout version you need to get the special low profile adaptor Steyr make, It's a slip on 1/2UNF type, I use with either a HW or Deathwhisper mod. It is a full free floating barrel so the mod will change the zero slightly.
The only 'issues' I've had are
1. the air cylinder can work slightly loose after a long time, Not a problem as you can just give it a 1/4 turn back into place.
2. The grip is stippled, which attracts dirt and grime, so i'll likely get a new stock from GC when possible.
Be prepared to shoot a lot of ammo if you get the SA version