I was thinking of using a bit of Christmas money to buy one of these for my commuter and do away with the chain tensioner. Can anyone recommend them?

they look nice and work well for rim braked frames.
the disc brake version is apparently a little more tricky to set up.

I would be using it with rim brakes.

i use one on my SS CX bike, works a treat, RECOMMENDED

I don't have any experience of the hub, but I use their Eno freewheel and it's awesome. I'm very impressed by the quality of it and so wouldn't hesitate to buy anything White Industries… lovely stuff.

PS my only gripe would be that WI have now made the fixed side if the hub splined so that you have to use their sprockets, i found an older 2nd hand one with threads as opposed to spline

The splines wouldn't be a problem for me as I'd never ride fixie on the road — I like leaning into corners too much.