I also think that the Pro1's opening mechanism is much more robust.
However, let's be nice among keyboard-lovers and recognise that the AstroSlide will have the much better keyboard -- probably more or less identical to the one its precursors had. From all that I have read, it seems to be as close as you can get to a "real" 10-finger keyboard in a PDA.
In all honesty, I find that the Pro1 is some "in-between" solution that seeks to be compatible with, both, thumb-typing as well as multi-finger operation (when the phone sits on a table). As a result, it fulfils both roles pretty badly