I'd spend the extra on a used SB600. (approx £150)
I've got one (for Canon), ETTLII works a treat on and off camera, and the external build quality is spot on. Their quality control can be a bit patchy, but on the flip side there have been people hammering their flashes for years without issues.
In terms of specs, all it really lacks over the top canon 580EXII was high speed sync, commander mode and weather sealing, none of which are an issue for me.
I find it simple to use, both on and off camera, and ETTL II works perfectly well wireless using the 7D internal flash as the commander.
The quality issues all seem to be linked to a capacitor, but apparently it can be replaced very easily should it fail outside of warranty, the actual physical build is top notch.
I bought mine from Photo Gadget, because they have a good rep on PoTN, I'd avoid anywhere that doesn't offer a 12 month warranty. If mine goes wrong I'll have to ship it back to China, which isn't ideal, but they seem to have a good returns policy which is the main thing.
I have a stand, clamp, umbrella and gels arriving this week too, I've spent a grand total of 130quid on a "starter" strobist setup that I can also use for "normal" flash work, can't really argue with that![]()
Oooh I'd be interested to see what you've ordered, from where and what your feedback is as it sounds like you are going in the same direction I'm wanting to go.