Hey Bish,
Like Mark said, depends what's popular near to you! We've ran both GT12 and LMP since quitting the micro scene. I have to say, I'd recommend LMP to anyone. They are absolutely rapid and a lot of fun to drive. GT12 is also great, but I found it a little tedious at times.
Both great classes but LMP cuts it for me
The extra downforce, grip and more tuneable chassis' makes them ace.