If you use 'quick look' (right click menu from the finder), you can scroll through your photos from the finder without opening them individually through preview. Works much in the same way as you're used to in windows.
I get on just fine. All my images are contained within my Aperture library, which manages all elements of editing and archiving. If I need to take them out and into another program, I'll export and then re-import - which is never tbh.
Surely if you used something like LR, you could open directly into PS? I'm not a LR user, or a PS user for that matter so I may be mistaken!
Quick look is just the same as spacebar, great, except you can't zoom in with that setting... It works in much the same way but doesn't have anywhere near the same amount of usability to it.
So you use a piece of software, basically the OS isn't actually the productivity increaser (although obviously you need OSX for Aperture). I actually use Lightroom occasionally on my desktop but normally I don't take thousands of photos so don't need database/sorting software like that (I still import most of the photos I edit - half dozen to a dozen max normally - into photoshop as I need that extra processing/editing ability Aperture and Lightroom doesn't have).