I have owned them all and while most high end trap guns are very good The combo that I have kept the longest is my current Blaser F3. Mine is a current model and has been flawless. In my honest opinion the F3 has the best triggers on the market. All The barrels being interchangeable with no extra fitting is a big plus also.
The earlier trap combos definitely had problems breaking the ribs. My girlfriends son shoots a earlier F3 combo and has had the gun back to Blaser three times for trigger (pull trigger) issues. You can't get any parts except through Blaser. I'm guessing they have most of the issues worked out by now.