1. The stock tips work well enough, and if you wear them over your head "shure style", then they are very very comfortable.
2. Soundwise, I think they sound pretty great for their price. The bass is definitely there, but not overpowering or muddy. The mids are a little muffled because of the bass, but you can still hear it. The highs are great too. I would put them above the Creative EP-630's and the Sony Fontopias. I don't have experience with any others to comment.
3. This is the purpose of this thread, really. With the stock tips, I feel like the isolation isn't that great. I can hear my tv going at a normal volume, I can hear myself clapping as well. I don't think it's that good at isolation which is why I'm asking about the tri-flanges for better isolation and possibly better sound.