My only concern is I rode one the other day (only around the car park at the bike shop) 56 frame and my feet were overlapping the front wheel.
It is if you are going to use it off road on anything that is at all trechnical!
Also, check the BB height - cx bikes sometimes have a higher one than road bike - makes clearences off road better, but if riding fast on road it might change the handling a tad.
I'd look at it all like this:
-for touring the galaxy (or others of that ilk) will be great
-for commuting the galaxy (or others of that ilk) will be great
-for off road the galaxy (or others of that ilk) will be acceptable (many of the previous generation of cycloX rider used to use an old tour before the big companies realised that they could make more money by making the bespoke cX bike)
-for touring a cX bike may be OK, but might have more flex, less comfort and less luggage carrying capacity
-for commuting a cX bike may be good, assuming it will take guards and a bit of luggage
-for off road the cX bike should be good (although note above about toe over lap)