The display is hard to see. At "normal" wrist viewing angles all I see is black. I have to tilt the watch and dodge reflections.
Despite the difficulties the black display looks cool and is quite usable. The main functions are large enough to read once you get the angle right and tame ambient light reflections. Under back light it's fine.
Other than that the watch is great. I get atomic time corrections easily (WA state USA), good compass readings, good barometer data, good temp and altitude readings. My watch seems to charge OK under a LED lamp.
If you can get the non-black display it should be be easier to see. The black display watch is still awesome, however, and looks better IMO.
The manual is essential and contains roughly 119 pages for English. You'll need it. As far as watch manuals, it pretty normal to OK, but still Casio would benefit if they hired an Oxford English major to polish the English even more.