I'm happy with my ST4.
Last bike was a Whyte 46 = Ultra High bottom bracket, and yes, I am cracking the pedals all the time with the ST4 – will take a bit of getting used to I guess.
And this might just be me, but every time I change down to the granny ring I have to remember to ease off the power, otherwise it sucks the chain up right past the (square) chainstay, where it gets properly stuck. It's an off the bike/chain off job to sort out.
Had it two weeks and so far ridden Lee Quarry, Cwmcarn, FoD and Cranham. The traction is as good as they say it is, and I haven't felt like I've bottomed the suspension out yet.