You might want to post this in the kegging section, but anyway...
There are definite advantages to having a dual regulator (dispense at different pressures, force carb one keg while dispensing another). I assume the 'B' option also comes with a regulator, otherwise it's pretty much useless.
How would you be dispensing the brew with option 'A'? Picnic taps?
Generally speaking, I'd probably get 'A' because of the dual regulator, and you really want to have at least 2 kegs...then later on get at least 2 taps worth of conversion for my extra fridge...
BTW, when you do eventually get your taps, spend the extra money and get Perlick faucets!
Packaged: Dark Munich Citra SMaSH, Mayan Stout, Caramel Quad, Basic Spiced Cider, Spur of the Moment Graff
Recent Meads: Mead Day '11 Ginger Metheglin, Mead Day '12 Traditional (orange blossom) Mead, Fresh Simple Cyser '12, Cherry Melomel, Belgeglin, Bochet
Secondary: Why do I keep this line here...?
Bulk Aging: Cocobochet
Planned: Hop Metheglin #3 (NZ hops), Trad. Gesho T'ej