I've had my TRG42 for 5+ years now and love it. I shoot Hornady 285gr Pills down it and get .4" groups @ 100m from bench rest.
The trigger is awesome, fully adjustable. As stated replacement parts are expensive.
I put a rear mono pod on the stock and Terj's check piece, and the stock now allows me to shoot all day.
I have worn out the front bipod though, which is dissapointing. Too much forward pressure and the steel indent on the leg deformed. A dremel fixed this.
The TRG42 is my 2nd favourite rig, my TRG22 is my favorite (.2" group @ 100m using Hornady 168gr A-Max).
Both have Schmidt & Bender 5-25PMiis.
In summary, you won't be dissapointed with the TRG.