The M5 really is a Swiss army knife of stomp boxes, and it does some of them really good.
I use it exclusively for modulation effects, Chorus, Tremolo, Delay. Basicly the stuff that I don´t use that often but is needed in a song or two. The OD part I don´t use at all, especially since I run it in the eff. loop of my amp.
For my amp I feel it sounds best in the eff. loop. When running it in front of the amp I felt that the effects started to get blurred up in the tone, that is not the case in the eff. loop,
It´s easy to use, but the way you change patches could be done alot better. Having to press both switches at the same time, and trying to see the display is a bit of a challange, and how it will work on stage I have yet to find out.
Quality leaves a bit to be desired since mine broke down after using it for a couple of days. Thomann was great with the service (as allways) and got it fixed, but I can´t really trust it.