So I purchased the Nanoverb from Alesis. It is really straightforward and the sound is not astonishing - but the quality is enough for most live applications.
The effects can't really be edited. There is an 'Adjust' knob that sets a fixed parameter (i.e. frequency of Chorus and so on) but that doesn't really qualify for editing. Also not Presets can be saved. This unit is truly 'quick-and-dirty'.
The whole thing is of course digital and has a stereo in, stereo out and bypass out on the back.
As I already mentioned the unit is truly straightforward. You have five knobs on the front: Input, Mix, Output, FX select and Adjust. So basically choose one of the 16 presets (Chorus, Delay, Flange, Rotary and Reverbs) and see what the Adjust knob does to the signal. That's really it - the manual really isn't needed.
The unit is built very well and the five knobs give a very easy overview on the parameters - this is what makes it excellent for Live. If you want to you could build 3 NanoVerbs into one Rackspace.
I found the Chorus, Flange and Rotary to be ok at best. I don't know where I would be using them - surely not in the studio. And Live I just don't really need these kinds of effects.
Delay and Reverb are very nice for Live applications - again in the studio I am not so sure. I think I would prefer a Plug-In or look for a more specific effects unit.
The reverb sounds are quite dense and you need to be careful to not make the signal too wet. In the right ratio they are very usefull - too much and the signal is lost in a sea of sound.
I bought this unit a few years ago and must say that I have not used it as much as I intended to. It is however nice and small and Alesis has always been very good at making good quality devices for a decent price. I don't think I would buy it again as there are simply better solutions out today. On the other hand I am not willing to sell it because its construction is very solid and it is very easy to adjust the sound.