The best thing about this service is that it has been around long enough, so there's lots of other people using them as well! It can be hard sometimes when their support team doesn't work fast or efficiently (sometimes answers are slow).
Also I think they should have more options in regards to payment plans because some users don't want to pay monthly just yet. If you're looking into getting proxies through an agency like us, then make sure your budget allows you to do so. We've realized we could save quite bit if were able to get our own direct connections instead of going through another party.