you probably won't see enough difference to be pleased by the cost (I still think of it more as a donation, so speed doesn't matter).

However, since you are seeing the same problems with LimeWire as with Bearshare, you know it's not a platform problem.

Frankly, I'd wonder about your internet setup, like virus, firewall and router controls. If you are confident those are set up properly, then I'd check out whether the ISP is implementing filesharing throttles.

btw, a decent check is to download one of the free files from www.magnetmix.com. If those download at respectable speeds, then the problem is with the sources you usually choose for the downloads.