To get the discussion back on track, the multi-class server was intended to emulate a "Le Mans" style of racing. So personal preferences of same-class one-on-one is not really the focus. You can find that on almost any server.
Does it work? Yes and no.
Is it the best racing? Depends on your own opinion.
One thing I can say is that the advent of multi-class (more than 2 classes anyways), has greatly increased some people's awareness of what's in their mirrors.
I took part in setting up the insim configs to facilitate what happens on IHR, and even though I may not totally agree with having such a great variety of cars on track at once, I can say that it has taught alot of people how to go about the often ignored Blue Flag rules.
Fact is, there are over 900 servers available, and more added on what seems a weekly basis. You just gotta find your niche.