I have had an exo for the whole of this season eventing,when l first looked at one l thought l would hate to wear one but within about 10mins of putting on on it felt no different to my old 'ordinary'one,it is very comfortable and would definately recommend one although they are expensive!
I dont think you can compare the EXO with a Charles Owen one.... fact of the matter is, if you were run over by a range rover wearing the Charles Owen one, you'd get squashed, however during testing of the EXO it was run over by a range rover and obviously didn't squash!!
If you are wearing an EXO and competing you have to make it known to the medical team so that they have the correct key to get you out of it should they need too!
ive got an exo and i love it (apart from the price) but IMO its worth it, just in case.
once youve got it on it doesnt really feel any different to a 'normal one'