I love the Muzzy 4 blade 100 grain broadheads. I've used the spitfire and the thunderhead, but I've seen better results with Muzzy. I'd either go with the 3 or 4 blade Muzzy's.
I'd also heard of people losing deer because the spitfires broke when hitting bone, which is not always an awful shot, but I try and stay away from bone whenever I can