A detuned chassis' Jesus Christ that is a desperate piece of writing.
Indeed. And total bollox. In what way is the new version "detuned"? There is no evidence of this at all.
I suspect there is some politics behind this. If you look at the reviews of the older ST4, everyone was raving about what a fun capable bike it was. A few of us went out + rode them fairly hard + they broke, hence the redesign. Maybe Orange asked journo's to reign in the rhetoric a bit?
That said everything that was said in the old reviews is more true about that newer frame, as Alex said above. It isn't a super efficient XC map crosser, or ideally suited for coming down Nan Biel the wrong way, but it more than capable of hamming round trail centers, down rocky trails /steps and handling smaller jumps + drops. I've yet to ride anything, where the bike was holding me back + its faster than my Prophet was on everything I've ridden it on. More importantly it feels faster + like you've got to pay more attention + put a bit more in to really get the most out of it. (In surfing terms, more like pumping a short board, than just standing around on a longboard). The downside of this is that after 4 hours you're pretty knackered. Testing a bike like this on old school XC death march type rides is pointless, its not what its for + if you're not getting full travel out of it, you really, really aren't trying hard enough. (Sorry Chipps)
Having also ridden the RZ120 It also is a very good fun bike, back end "feels" stiffer + probably can be built up into a lighter bike + would be a better choice if you are planning more endurothon rides.
Try both, if you are anywhere near West Wales you are welcome to have a play on my ST4.
I think this highlights the fundamental problem in bike reviews. They are not based on any objective testing of measurable qualities such as stiffness or efficiency. Not saying we should go all tutonic + have reviews in the form of tables of figures, but some evidence to back up manufacturer's claims and journo's opinions would add objectivity.
I was going to write something similar after reading the STW review. But you've saved me a job! 
