In fact what will, today, make me chose the Langematik perpetual is that I want to wear this watch during the week so, as I'm not a how-happy-I -am-when-I-manually-wind-up-my-watch-every-morning fellow, at all, I really like the fact that it is ... automatic.
The thing is that in this case I must draw a line under the Dato's back :/
Furthermore, I think I may prefer the Langematik perpetual's proportions (thickness) and its dial's harmony as I'm focusing the platinum version (but may be the Pink gold for the Dato).
In spite of that, if I had to chose the one I would wear only once in a while, then I wouldn't need the automatic display and hence would chose the Dato, as finally the line is really thin between the 2 choices.
Tell us how your mind evolves !
Best;
Mark