I'm old-school, but I've tried dozens of brands, mechanical and fixed, and find myself coming back time and again to Thunderhead 100's or 125's.
They're durable, you can buy replacement blades just about anywhere, and they will probably be around for a long time.
I've had some good kills with mechanicals (Rage, Rocket) and they do cut a good hole allowing for a big blood trail. The problem lies in that 'just slightly off' shoulder shot that requires blowing through a very tough (on bigger deer) shoulder blade. I've seen, on a friend's buck, the Rage NOT do a very good job when the shot angle wasn't optimal.
And I've heard horror stories about the mechanicals freezing up, as well. Personally, my problem with them is that sometimes they just deploy a blade or two and you have to snug them back up after walking through brush. The less you have to think about during a hunt, when it comes to equipment, the better.