untill last year i would of never used an expandable broadhead. i had sucess with fixed blades and the way i look at there was no reason to change. untill i found by self board one day and bought some 3 blade rage heads. i did some of my own tests. the result were great. huge entry holes and huge exit holes. i shot my very nice 10 point days after buying them and will be using rage for years now. the above mentioned 10 pointer was very slighthy quartering away, a shot that is not perfect but with the hoyt and rage combo the arrow blew right through the buck with a double lung shot. the blood trail was remarkable. he ran about 50 yards and fell over. when i field dressed the deer, it was remarkable what his lungs looked like, they were shreeded.
most of the heads on the market today will do the job, fixed heads or expandables if properly tuned. for me the most important thing is to have confidence in what you are shooting. if you have worries about your heads try some other heads untill you find something that you have no doubt in. fixed blades or expandables.
doing your own tests on heads can be a bit pricy but it is a fun and you can learn alot shooting into different materials.
good luck hunting