What you really need to be asking is, what classes will this new track be running. That said, the 1/10th TC classes seem to be most common in general. I believe this new track is outdoor asphalt, which probably means it's not likely to see much pan car action.
Regarding "fun" vs "competitive", it really comes down to the people involved. Some of the slower classes are actually more competitive than the faster ones depending on who's racing in them. That said, VTA and USGT are generally considered a "fun" class in a similar vein to SCT. For the 1/10th TC classes, many see the slower classes as beginner classes and the faster classes as the competitive ones. You'll still probably see some very competitive drivers in the slower classes though.
The main differences between VTA and USGT are bodies, tires, and weight limits.
F1 is a great class if you can get the numbers. Some areas struggle to keep it running.
I don't know of any 1/8th scale electric on road classes.
I personally run a TC3 in both 21.5 sportsman and 17.5 "GT" classes, and a Tamiya M03 in mini (under Australian rules). Mostly because that's what I had in the cupboard when I pulled them out of retirement earlier this year. I race on a budget for the fun of it, I'm not aiming to be super competitive.