A few of the fastest guys locally recently switched to Xray from TOP, Tamiya and Corally.
I love my 2 Photons. It took me a while to learn how to build everything right and a few upgrades to get my cars to a point where they're pretty durable. Out of the box, some of the plastics seem to be either too soft or too brittle. Front dogbones have to be changed from alloy ones to steel. Their screws generally suck and the ones they give you for the suspension mounts should be longer. Kit bumper is too soft... There are many things I could say that could be considered negative, but I really do love my Photons. I just know all of their idiosyncrasies now.
I'm sure some TC6 guys would have all sorts of things to say about what could be better on that kit too. From the handful of them that I've seen at the track, the word "durable" is definitely not
something I would use to describe them. I've seen bearings blown apart and a couple of epic carnage yard sale crashes. Broken bits everywhere. A big part of that is probably the guys who were driving them though.
I doubt I'll change brands anytime soon, but if I was to start fresh today, I would probably buy an XRAY T3 '11. Everything costs more, but it is excellent quality. I can also get good support locally.
I think all of these kits and many more, can win championships, if set up and driven by the right set of hands.