Going to failure can be very misleading. Sounds like a great training idea but it can fall short if size and strength is the goal. Overly stressing the CNS and tapping out the recovery abilities only slows, or even halt, gains which going to failure can do. If you think that you can get 1 or 2 extra reps (with spotter or not) with all out effort than do not. As John O suggest, have at least one (or sometimes two) extra max rep as a cut off point. Guy's who do go to failure every rep, every workout, are only cheating themselves of progressive gains. Than they wonder why they look the same year in, year out. Some confuse working extra hard and the need to go to failure each set. Very big difference in that regard.
If your juicing than you may or may not get away from going to failure from time to time. Even high quality 'roids do not work the same on everyone. Some guy's will thrive on them and other will make only minuscule gains. Using 'roids is not always the miracle drug for everyone. Forget about the video's for sale about the "real" way the Pro's train. Most of those guy's do not go to and beyond the true point of failure. If they do not, than why should you? Good Luck.