It's comfortable but reduce the bass. That is what I noticed when i use those tips with u12. I will try with my second vega when it arrives on Wednesday.
Personally, I found that the foam they used was too hard. Put too much pressure on my ears that just ended up turning into pain.
As far as sound, people seem to talk about the tips making a huge difference on sound... I found it very minor at best. They sounded similar to other silicon tips to me. The only tips that sounded any different were the included foams, they seemed to smooth things out a bit, but I have a hunch thats more because I dont like foams and have trouble really getting a great seal with them.
Thx for the feedback, looks like I'll stick with the Campfire foams for now. My sole issue with them is the need to keep replacing them, otherwise they're great. Been trying the Spinfits but they make the bass a bit too bloated. Maybe one day I'll go nuts and order 300 foam tips.