None. Placement of the input nipple being high on the reg is not bothersome whatsoever.
Lightest marker I have ever held. Your exact words will be "Wow" when you pick one up. There is virtually no kick whatsoever. It was allready said in another review, but I had a DM5 which has very little kick, and this marker will make you notice the DM5's kick. The trigger is absolutely awesome. It's extremely comfortable and there is no sideplay whatsoever. The trigger adjustments are extremely easy to use and put other trigger adjustments (especially the DM5's) to shame. The stock barrel shoots straight, so there is no reason to put a new one on unless you want to use a barrel kit like the Freak. The marker is very comfortable to hold, which is also largely due to how light it is. When you open the bolt you'll think you're missing something when you see it's only two pieces, well, you aren't. The board is very easy to program using trigger pulls and different colored lights. It even has a tournament lock. Am I allowed to say how light it is again?
If you ever get the chance to hold or fire one of these babies, I guarantee it will be your next marker. It outclasses anything I've ever shot, I had a hard time writing a review because it's more of a "you have to shoot it" type of thing to understand how great this marker really is.