Caverject works GREAT for me.
I use it in conjunction with Cialis. I'll take 5mgs of Cialis (or generic tadalifil) in the morning of the day I plan to use Caverject, and then anywhere between 5pm and midnight I''ll inject 20mcg of Caverject and it works GREAT. It'll give me an erection for about an hour and a half.
Since everyone's body reacts differently to the same drugs I would advise experimenting with half of a 5mg pill of Cialis first to see if that is enough for you (If you're interested in using Cialis with Caverject).
If you jump right into the dose that works for me you might possibly end up with priapism, so start with a small dose and work up based on how your body reacts.
And Yes, I have used Caverject WITHOUT Cialis and I still get good results, but with Cialis I get GREAT results and GREAT is always better than good.