It probably depends on where u live - the Poplar proxies seem to be pretty bad a lot of the time, ebuyer,microsoft and others all stop working for random amounts of time it seems, others on the Poplar Proxies have reported similar problems, added to that for a few weeks after the speed upgrades they were incapable of reaching the advertised speeds on US sites because of a misconfiguration.
I've also noticed slowdowns again recently, switching to other NTL proxies restores full speeds - they are definately a pain in the bum if you live in this area
