Don't get the Summit one if it looks like the photo, since for GM (don't you hate those "representative photo"). Note the tilted bracket and threaded rod. GM had a strange design where the same brake pedal was used for manual and power, with holes at different heights (for different lever ratios), hence they had to tilt the booster.
I would get the $289 one and it comes with an adjustable proportioning valve (probably don't need the residual valves shown). It is also a double-diaphragm booster (as is MP one, $300 one looks like a single). The others have heavy cast-iron MC's, and who needs that. You can get the 2-hole alum MC at any auto parts (have read it is used on 90's Dodge trucks).
Or you could be a cheap Mopar bastard like me. I put a booster & MC from a 96 Breeze on Dart stand-off brackets. Works great. Well actually barely clears the after-market valve covers on my early A, but 3/16" is plenty.