Anything that is of quality....simply don't ever shoot crap unless you have too.
Unique Designs(i got the Joydivision)
Have to you use rubber squeegee, not necessarily bad.
When getting this or any barrel, i don't reccommend getting a kit or multiple bores if shooting semi. Get a larger bore .691 or .693. This way you will be able to shoot anything out of your barrel and really with ease and accuracy. I was still putting ball on ball with small .684 paint in my .691.
Now the thing about this is it will shoot just like a AA or a UL and for the same price as a UL it is a hellova lot lighter. Some say they can break? i haven't seen this nor believe it. It is a very sturdy marker.
Great barrel, the new line though is just cosmetic if you want more for your money get a basic one. This is just a cosmetic improvement.