I've managed to twist and/or break several of the previously listed brands of Torx bits, usually while trying to remove fasteners that some doofus overtightened previously. IMHO, one serious flaw of the Torx design is that (especially in the smaller sizes) there just isn't enough material in each "tooth" to avoid breakage or twisting when you exceed the torque rating of that size fastener. Somehow we've gone from the Phillips bit that tends to destroy the head of fasteners, to the Torx bit that destroys itself. Both were inventions meant to make life easier for folks screwing lots of parts together using power tools and automation, not so much for folks just using hand tools to take the stuff apart.
Snap-On does indeed make some of the best hand tools around. Of course, you pay through the nose for that quality and the service provided by that guy in the truck that comes by every week. If you use your tools to make a living, it's a good choice. If you're a weekend warrior and occasional wrench turner, it's not worth the price. And if you aren't a pro, that guy in the truck isn't going to stop by the house to see what you need and replace broken tools. Stick with the much more readily available Craftsman, which has the same guarantee and much better prices.
JMHO - Jerry