well from my experience in my cycles the only test ive ever ran so far is test e. Last cycle consisted of test e, deca,winstrol,eq. Bit of a long cycle. Bulked first half with test e and deca and then ran a cut with test e, eq, winstrol and also had arimidex involved throughout. Ive been off now for about 6 weeks. All in all I would love to say i retained all the mass I put on during cycle but i would be lying. However the fact that after a good PCT, my natural test and all levels are back in order,my weight is 7 pounds heavier from when I started and body fat is bout the same again(was lower,wont lie,been enjoying some food etc. i missed for a while.haha) but my muscular mass gain is noticable in both terms of visual and numeric so even with 4 compounds incorporated throughout one cycle,I would have to say that yes, test E will get you long term gains if you train properly,eat right,and do a proper PCT

That depends on a lot of things, What if your body fat, how much test, how is your diet, you will definitely gain mass but its up to how you train and diet that will determine how much is true mass. Also a good pct is key to retaining a large amount of your gains. Goodluck