First what is your cycle history? Stats?
I liked test 400, its very similar to sust. One thing to note is I always had an irritated injection site, it hurt to inject a little and it was itchy. I never got an infection, but I am under the impression that they need to use a higher amount of BA to keep everything suspended in the solution. I am not sure, but that was the experience.
Anyhow, if this is a 1st cycle just go with test E @ 500mg for 12 weeks. If this is not your 1st cycle, just note that you should shoot it 3 times per week to capitalize on the propionate. That should help keep blood levels more stable. Other than Prop, there is Cyp and E in it, so post cycle therapy (pct) starts after 2 weeks.
EDIT: Oh yeah, I didn't answer all your questions. I would try not to ever use it again, or sust. I tried both and I do not see their purpose. I am much happier with a few vials of prop and a few of enth. You have more control and can prop while the Enth is clearing out.