I have seen the Turn A movies, and like you I had some reservations as I didn't like the MS designs (the original ones anyway).
However, once you start watching it, it's got a good story (different, but still kept the primary theme of Gundam), good characters, and the Mustached Gundam starts to grow on you; I think the reason why it actually looked better as it went along, was the fact that they did an excellent job animating the mech.
It's movements were smooth, yet still moved like a machine.
Overall, I would recomend watching Turn A.