Test only cycles are great. The highest I've ever run is 600mg Test E. I get super gains on this and haven't yet felt the need to go higher. I'll be the first one to admit that I get caught up in trying to add too many compounds into a cycle. I've never felt better IN MY LIFE than when running just test for about 10 weeks.
I really think Test/EQ may be the perfect cycle tho. You get good size from the test while the EQ keeps you lean. The EQ also helps to restore/improve collagen synthesis that test may slow down. The biggest thing is that I seem to get no additional side effects when adding 600mg EQ EW. Other guys I know run a gram of EQ and feel absolutely awesome.
Someday I'm sure I'll run a gram of test, but I really don't feel I need it at this time. And it does appear that some guys respond better to higher doses than others, so I always give people the benefit of the doubt when they run really high doses. If you can run that high of a dose without severe side effects......more power to ya