I'm thinking of buying a rear atomlab hub, but I dont want it to be a wasted purchase as I dont want a hub that isnt compatible with wide calipers such as my Hope C2.
Does anybody use one, and have they anything that i need to know about them before I buy one?

I guess not then.
Any other recommendations?

Hope?

I'm looking to spend about £100 on a rear wheel, so not even a Hope XC will fit into the budget.

Yes it will! Hope XC on Mavic X517 is £103 from Merlin. Add a couple of quid for an F519 or D521 rim. That's "about £100" in my book!

arent hope xc hubs £90 alone?

From some places yes. You normally find a fully built wheel from somewhere like Merlin, Chain Reaction etc. is cheaper than the component parts purchased separately. Don't ask me why, just take advantage of it!

Be wary of mail order wheels. They invariably use cheap ACI spokes or plain gauge DT and you have to pay extra for double butted DT (usually far more than the spokes cost!). A lot of the time it doesn't include rimtape either!Watch out for postage too.
Topshelf Components do professionally handbuilt wheels on Aireal Industries hubs (better than Hope, from australia so they're cheaper, all cnced with good bearings) on mavic rims like 521, 517, 519, 219 for £100 incl postage (DT double butted spokes, velox cloth rim tape, everything). Cheaper than buying the parts?
They import the hubs so can do really good deals on builds (hub alone is £70 i think)

The Aireal stuff looks really tasty but where do you go to for warranty?
According to their website, they do not yet have a european distributor.
As it stands at the moment, I'd stick with Hope but I do look forward to seeing the Aireal stuff in the flesh.

Mmm. Those cranks and chain devices are mint!
I've always wondred if Hope will ever make a crankset or a chain device.