There is no "Best" indoor sativa.
There are too many factors to consider. Some take up to 24 months to flower while others finish in a shorter amount of time. I'm currently growing an Oldtimers Haze that can take up to 24 months but I've also grown Durban, Ciskei, and several others. I've recently acquired numerous landrace strains from The Real Seed Company. I haven't started any yet because I haven't figured out a game plan to grow them in a 4 x 4 tent. The problem with sativa's is they take so long that they won't finish outdoors where I am at. And they get so big that they're hard to manage indoors. Plus they're really finicky when growing in containers and with their long flowering times there is plenty of opportunity to screw them up.
ACE, Cannabiogen, The Real Seed Company have some good sativa genetics.
Fairly recent picture of an Oldtimers Haze at about ten weeks flowering with at least another 8 weeks to go. I hope I make it to the finish line. My last attempt growing this ended in failure. This one was started outside and got so tall I had to do some serious supercropping to fit it inside. With proper training early on you can grow any sativa indoors. But if you don't keep an eye on them they can get out of control.