I've seen both bands live (although filter was a long time ago... 94 or 95 maybe) and they both put on a great show. However, tool live is something special. Especially tool live in 95 at a small club. There are few bands that have the kind of stage presence and ability to utterly mesmerize a crowd.
I've yet to hear Filter's latest album, although I liked short bus a lot.
I actually have to go among hte I don't like Lateralus crowd. Opiate was always my favorite tool album, and it still is. Undertow and Aenima were both wonderful, unique albums, but they lacked the energy of Opiate. Lateralus lacks the energy and the flair IMHO. Too wandery.
I still voted for tool