I like to train to failure but in different rep ranges, and I do it "heavy duty" style as Arnold named it in his book. Meaning I start with a heavy weight not a light one. So say you are doing bench press, you do your warm ups then a heavy set to failure, then a medium set to failure and then a lighter one. This is all Phil Hernons by the way. I wouldn't have posted this in the open before but if you read his training threads from the last couple weeks he goes into it there.
I also had very good luck with Dorians style HIT where each exercise gets one work set. I would vary the poundage a little bit from week to week so I wasn't always in the 6-8 rep range.
A lot of the golden age guys talk about taking each set to failure(Arnold for instance), but I just don't see that as feasible for most of us. I you are doing 15 12 8 and 6 rep to failure sets by the time you get to your "heavy" set, it's not going to be very heavy and that to me is counter productive.
I do like the volume routines put out by Gironda and Nubret. They increased intensity by volume and shorter rest periods. Gironda especially was all about doing the same amount of work in less time. You get cumulative fatigue in the muscle not going to failure but by doing lots of sets and focusing on form.
This can also work very well IMHO.
Mountain Dog training is a high volume and can be heavy weight as well but it's not focused on going to failure each time. Sometimes you might but not every set every exercise.
I think doing alot of volume AND training to failure is a recipe for disaster. It may go ok for a couple weeks but then you are either going to be burned out or injured.