For the ridiculously complex models I normally make, I wouldn’t even consider using Hex - thank goodness for UU3D:) Can make groups, UV map each in any number of ways, combine groups afterwards. The only hassle I have with it is selecting edges to cut seams, which can be very painful because it is too accurate and selects every branch of edge loops.
If only I could select the seams in Hex and then continue in UU3D:)