If a voicebank is on axfc, it can stay there. I will not go there, I don't care how much I want the voicebank, heck no. I don't want to risk someone walking past me and getting a face full of hentai before I can hid the tab, or by chance someone looks at my browser history. Heck. No. Also, no 4shared. Nope, I don't care how much I want the voicebank, also that one site Matsudappoiyo was on, nope. Never. Again.
Mediafire is a bit sketchy, I don't really like it, but it works. It's one of those sites you have to be careful on.
Dropbox is pretty good, but you need to pay to password protect files, so I don't use it to distribute voicebanks, but to hold on to them just in case.
VocalSynth cloud is thus far one of my favorite sites for UTAU downloading and uploading, limited space is bit of an issue, but aside from that, it and bowlroll are my favorites and go to sites. I lean closer to VocalSynth cloud because bowlroll is in Japanese and that's a bit of a nuisance for someone who doesn't know Japanese, such as myself.