Their support blows. The owner is a kid who might know how to setup proxy servers, but he's not too bright when it comes to running and maintaining them in an efficient way. If you're not concerned with speed and strength then they will probably work. However, don't try to make too many concurrent connections or you'll waste your money.
Even if he does respond pre-sale, don't believe much of what he says. I asked him (and I still have the email) very specifically to give me proxies from the subnet's/servers so I could make sure they'd work out. He sends me 5 proxies from 5 diff ranges and they worked great. When I got my actual proxy list that I paid for, 750 sequential IPs on 1 subnet, 250 on another. LOL. As soon as I put the slightest bit of pressure on them they started to bump each other offline. To be fair, he did swap them out, but it was always a good 10-12 hrs minimum before he'd respond to any email I sent, and it still didn't matter. If you're not going to be slamming them though, and just need as many different IPs as you can get, you can't beat the prices. Just keep in mind that you get what you pay for.