I installed Frostwire this morning. It did an uninstall if Limewire during its own install, which was ok. It somehow added an ask.com toolbar, which wasn't ok. I didn't notice it as an optional item during install. It may have been in the TOS section.
Otherwise, so far so good. It certainly seems faster, both with search results and with download speeds. I didn't set up any A/B test to confirm this. The only problem was I couldn't preview any song with my default player that was still being downloaded. The option was there, but it wouldn't respond.