I find Phex is better than either LW or FrostWire for obscure downloads. This is because LW tends to connect/find mostly only other LW users. Whereas Phex finds files from 'other' Gnutella programs. FrostWire is very similar to LW, being basically the same code.

Difficult to compare Gnutella network & bittorrents. They are somewhat different. I also use Azureus and am very happy with it. I use Advanced settings for mine.

There are a lot of sites around that use Torrents, but many you need to sign up for. I am not as experienced a torrent user as many others on these forums so will not attempt to answer your question. I use both to find the rarer files. If I have difficulty finding it with one then I will try the other. I use both LW Pro, Phex & Azureus.