The only time I have ever used reverb in a mastering setting was on an acoustic, live-to-2-track, semi-'classical' project: I needed to create a decent ring-out/decay for an otherwise good take that was spoiled by someone dropping something at the end. I programmed up a reverb that matched the sound of the room as best I could, and automated the send to it going up just on the last "boom" of the music, as the actual recorded tail was faded down before the offending thud could be heard. Worked nicely.
In any kind of pop or rock music, the thought of adding global reverb gives me the willies. No thanks. I just can't think of a situation where it would sound like anything other than cheese. ...
Of course, no offense to the dairy industry.