i don't have, nor even tested the FA43, but i have the DA*55.
Yes, it's sharp. wide open, all is about nailing the focus. @f1.6 it's become really sharp, f1.8 it's unflattering for the subject
The color are very well saturated, not to much, just what is required to make every color shot "pop". To be honest, that my favorite lens by far.
Yes, it's expensive, the AF is not fast ( or always reliable on my K-x - thank you huge focusing points ... more to do with the body than the lens, i'm sure). It's WR though.
But : if you like the 50/55mm FoV on APS-C (or film - my most used lens on cheap film body that have a KA or KAF mount), you'll be really happy.
Side note : the lens is large, but not heavy. Just keep in mind you won't be "unseen" by the others