It depends entirely on the context I suppose. To be honest, the ONLY thing turn based combat let you do was plan out a series of moves in painful detail - something useful in certain types of games I suppose. Personally, I never saw a problem with the semi-real time format in Fallout Tactics, Baldurs Gate, Planescape Torment, Dragon Age: Origins or Neverwinter Nights. Having 4 attacks per round translated to faster attacks in the D&D games, and at any time you could simply pause the game and select your actions which would begin on the next "round". In the case of the D&D based games, the game's turns were based on short lengths of time (seven seconds if I remember correctly) and thus something that took 3 rounds to cast required 21 seconds or so.
It worked out well enough that I loved all of those games. Of course, I would have prefered a slightly more turn based take on Dragon Age: Origins as it appears to be more or less an MMO in it's mechanical structure.