I've got two of these, bought second hand for less than £50. I have to say that I really don't like the sound of the reverbs on this. Saying that all the other effects are great! I mostly use the delays, but also use the chorus and flanger, my only fault with them is that they are too clean, but that's what you get from digital!
Obviously, this is not the best reverb in the world and should not be compared with the more expensive high-end stuff from Lexicon, Eventide, TCE etc.. which you'd put on some very nice vocals... but is good enough to use as a secondary generic room/hall reverb to liven up some tracks.
If you're after that kind of more Lo-Fi, unnoticeable, subtle reverb, as could find on some electronic tracks in the 90's, it should even be good enough to use it as the main reverb. It must be one of the best kept public secrets and people probably do not take the Alesis verbs seriously as they are not very expensive... Good enough to get the job done if you know what you're doing... A studio essential...