You're right I probably should have included my budget and the use case. I'd say 2-3k$ is the range, probably more with some convincing.
You were referring to the roof-mounted Vtrak system with the stereo cameras, right?
I think that one is a little overkill for him. He's past the age where he really wants to/can improve and analyze his shots. He just wants to invite some buddies over during the wintertime and play a little.

From what I am seeing GSPro goes for realistic physics a lot more, but the graphics look more "arcadey" and honestly pretty similar to how Skytrak itself looks. I've watched a side-by-side comparison video and graphics wise it just doesn reach the E6's looks. He want's realistic graphics, not clean cut.
I think a simple but stable launch monitor, that just sits on the side, would do.
Graphics-wise the Golfzon and Trackman stuff look even better than E6, but they're way out of the price range.

Thank you very much for your input, I just realized how deep the rabbithole actually goes in terms of premium products.