Why an either/or choice? I have - and use - T-handles, L-handles (long and short), ratchet sockets, fixed sets, some in ball-end, some in straight end. Each is better than the others at something.
For a first set (assuming you're working on bikes), a quality L-handle straight-end set is a good place to start.
+1
The basic L is a good set to start with. Get a set of balls when you can afford it to make those tight access jobs easier.
Th 1/4" or whatever size drive sets can get expensive. Bit sets are harder to find but more affordable:
Bondhus ball end driver bits - $17