I think Robo-war and the other Premier games were overlooked by most collectors until the last couple years (now that there are lots of videos of gameplay available on Youtube.) Before that, I suspect that they were passed over in preference to trendier games like the Williams titles, and DMD games. My guess is that there are still quite a few waiting to be found in the back of warehouses.
Personally, I like all the Premier games I've played, they tend to have unusual playfield layouts and fun, straightforward rules making them easy to like, and right away.
In my game room I have an Arena (underrated) and Excalibur (fun!) in my gameroom. Both are pretty simple games, but are lots of fun, and look fantastic with LEDs. I'd love to add a TX, Robo-war, Genesis, or Hollywood Heat if I could find any of them.
Any of you guys who have one of these, do yourself a favor and replace your backbox light with a new 'daylight' bulb instead of the soft-white that is usually in there. Daylight bulbs do not have the ugly yellow tint, they are more of a cool, pure white -- and your translight will look 100% better with upgraded lighting.