Hovering over "Buy"... care to sanity check my thinking?!

[JAZZCNC]

I know some of you seem to be fans of pulleys/belts; any reason to go that route? I don't need it for the gearing-down/accuracy as by my measure, even direct will give me the resolution I need (and microstepping, even better). Are there other good reasons to belt-drive?

The main advantage of belts other than gearing is to reduce resonance and smoothen motor performance. This is why most use it.
Resonance cripples the performance of steppers so anything to help reduce it is welcome. Using Digital drives makes huge difference to stepper performance and smoothness.
Also regards Micro stepping don't think of it to increase resolution because while it does up to a point it's main purpose is to smooth motor performance. Noticed you also mentioned running Steppers at 200 steps (Full step) this would make them run awful so expect to use Micro stepping.

but would my C5's be any different?

They are exactly the same regards end dimensions. But C5 screws require higher spec end fixings hence why they sell C5 end bearings other wise there's no point using C5 screws.