I am tempted to buy one of these due to the  "Plug-N-Play" valve connector which according to the manufacturer allows you to remove the tube and the fact that the bladder is reversible for cleaning. 

Should I risk buying one of these or stick to the more common other makes eg camelbak?

camelbaks have a big enough opening to get yer hand in there to clean it (not that I've ever cleaned mine). The tube bit has an anti-bacterial coating on the inside - so its as hygenic as its gets.

The Hydrapak looks pretty good though and is only a couple of quid dearer. I personally would go for the camelbak - spares available in any bike shop