Fluorescents--Direct/Indirect + ballast q

Has anyone installed some of the recessed direct/indirect fluorescent troffers? They're about to remodel my office and I was told I can pick out whatever I want and these seem to be along the lines of what I'd want. Ceilings are a bit low, so a pendant light probably would be out of the question. Does anyone have any recommendations on brands of these and styles? I see some of them have the bulbs in the center while others have the bulbs down the sides. Has anyone done a retrofit, replacing original troffers with these? If so, what is the light level difference like?

Also, what's the best ballast to use? Chances are the lights would be turned on around 8am and be left on until 6pm, so the rapid start w/the filament heaters running all the time seems like a waste.

Thanks!