I've had both of these shelters, so I thought I'd chime in with my thoughts:
The SL2 is super easy to pitch and a nice shelter for one, but I honestly found it crowded for 2. In contrast, the Trailstar was incredibly roomy, but a little more finicky to pitch. I found it difficult to really pin all edges to the ground to prevent wind from seeping in.
In the end, I ended up getting an MLD speedmid. I find that it splits the difference between mid and trailstar quite well, and fits two easily. It is also customizable (add bug netting, an innernet, panel tie-out points, etc).
I think it is hard to beat any of the pyramid-style tarps from MLD, whether it be the Trailstar or one of their mids.
Best of luck!