Turn based is easier to implment, and gives the
user more time to think about tactical choices.

Games like Jagged Alliance 2 are a perfect example of
turn based action.

Fallout 3 used a nice twist to the real time action, by
stopping the game, and let the user apply a shot to a certain
area of the target.

I think an apply-command-then-action vartiant is cool.
Where players assign actions at the same time, and then the
game runs for a certain time, perforing the commands,-- vs the
pure turn for each player mode.