I'm having a ball with the lower-tier stuff, and being in a TD is more fun than I would have guessed. I'm vulnerable as heck, but man can I lay the hurt down when I'm in a good position!
I just finished a fantastic battle that really demonstrated good use of the weapons at hand. I was hanging off on the edges, with the big scrum going on in the middle of the map. I found the perfect spot and racked up 3 kills out of the big melee, when I noticed a BT break away and come racing, RACING down the hill to come flush me out. I found another spot and set up an ambush, and got off a couple of really good shots before he finally got to me. I lost, but it was a very close thing. If I'd had even a light tank acting as security, I'd have made it.