That’s like asking what car you should buy, everyone has their preference. 😉
GarGraves with Ross switches gets a lot of support, mostly because of cost and availability. Ross arguably makes the best switches and has the largest variety. My problems with GG are the shortest straight track is over 6” and they don’t offer partial curved tracks, so there can be a lot of cutting involved depending on the design.
Atlas is arguably the quietest because it is solid rail. It has the largest variety of straights and partial curves. Their switches used to be problematic, but that was resolved years ago, though Ross still has more options. Atlas is also the most expensive as far as retail price goes, so you have to shop around for good prices.
ScaleTrax is arguably the nicest looking with their thin black center rail that almost disappears. It’s also solid rail, so it’s quiet too. Availability has always been a problem and no telling what’s going to happen with MTH products with Mike retiring next year.
FasTrack has a wide variety of track it you want something with plastic roadbed. It’s arguably the noisiest.
Tubular is inexpensive, but options are limited.