"Unregistered" in his uninformed opinion states

mactella doesn't give you : what file type to exclude
yes, it does. preferences > search

mactella doesn't give you : multiple folders to share
again, yes, it does.
from their web page: "Mactella fully supports the use of aliases. No need to move all of your documents and files into the Public Folder for sharing. Just drag an alias on in and let the fun begin."

Personally Mactella is a bigger pain in the tush to use, but I have more successful searches and more successful *COMPLETED* downloads with it.
Limewire is OK, the interface is certianly prettier and I still use Limewire too ... but who cares if there's 17TB of files available if I still can't find what I want, or if I am constantly getting "unable to connect" messages when I try to download?
To me getting the successful completed file downloaded, that's what matters. Mactella just delivers more then Limewire for me at this time.

IMHO - try both, see what works for you. while you're at it check out iSwipe too ( http://www.hillmanminx.com/ ). After all, whatever works it whats best for you.