i've used Gaspari SuperPump Max which i got addicted to but is getting more difficult to find. i have about a tub and half left. i've got Muscle Pharm Assault in the kitchen and will mix 3/4 scoop with one scoop Scivation Pyscho. i like that taste and even use it some mornings before work instead of coffee.
i take a break from it all once a month for at least 5-8 days and just drink coffee or green tea before workouts. well that and Gaspari Isofusion whey isolate.
have been known to do as said before make my own add 3-4mg of nutrabio's leucine and about 4-6mg citrulline malate, taurine to green tea that has sat over night and take it about 30min preworkout.