Ah, there are not many dedicated Tool/APC fans here obviously. Therefore ill be short.
IMO APC was one of the most refreshing and brilliant bands to emerge in "modern rock", and with their first 2 albums they managed to come up with a number of downright brilliant and meaningful, yet listenable and accessible songs. Really masterful. Billy Howerdel and Maynard were a great songwriting team. I listen to APC regularly to this day.
Tool however is already one of the most important and artistic bands in rock history, regardless of whether wide audience or critics recognize it (as of now!). There's this shift in their songs, true complexity and depth to both their music and lyrics, and i personally see Tool as the single most deserving band to bring sense of fine art aesthetics to rock music. I think anyone who has really given a chance to Tool (which demands repeated listens over a longer period of time) and didnt find anything big is entitled to his opinion, but i also feel that most of the opinions stated here were rather superficial, no offense. Check out Tool for real!