I think there's a misunderstanding from some people here about the priorities of a mining rig. no one cares what RAM it has, or even what cpu in most cases. If it is cheap, and allows you to ram loads of gpus in it and mine 24/7 reliably, then it's a good mining rig. Those aren't the problems with this concept.
The issue here is that because OcUK are going to have to compete for stock, their pricing is never going to beat 2nd hand (even at the extortionate rates people are selling at), and these rigs won't earn their price in coins for a looooong time. that's what makes them a fundamentally flawed product. The ROI is just not going to be there, unlike with a gaming rig where the experience of owning the hardware to run your games is its own ROI.
If this was the best way for me to build a farm, I'd do it, but mining is about ROI, and this doesn't really fit the bill. a dual 280x build will yield a maximum of £300 worth of coins at the current value/difficulty of most coins, so you're betting on difficulty remaining reasonably static for 4 months to pay this investment off, which simply isn't going to happen.
I'm not criticising OcUK for trying to get in on the action, but no one who mines is going to see this as good value, regardless of the great service OcUK would offer, because it won't pay for itself (which is the whole point of buying it) for a long enough timescale that the risk of it not giving ROI at all becomes much higher.