So far I have only dealt with Photobucket but from the little I've see with the way Imageshack handles its images, linking and pop-up add I'll probably stay away from it. I don鈥檛 know about it鈥檚 admin or it鈥檚 features but with the sh*ty speed or its server and the pop-ups that is enough for me not to use it.
I think eSnips is better than both Imageshack and Photobucket. First of all, you get 1GB free with no monthly limitations or anything. Also, you can upload any type of file, not just images, so it's useful for many other things. And finally, the community is much more interesting. For example, check out their photography community.