I'm a fan of the M series lights and own a few, M1.8 & M40. I wanted to LOVE the M8 like I do the others in the series. BUT, here are my thoughts. I was in the market for an 800w light so I compared the two, tested them both. The M8, while a very nice light, is not as versatile as the Joker 800 bug or zoom. The K5600 Jokerbug 800 Zoom is a lensless competitor to the M8. Here are the reasons I chose to purchase the Joker 800 Zoom over the M8;
Joker has a smaller head feeder and ballast, bother lighter.
Joker can be converted into a Jo-Leko configuration.
Joker fits nicely into their white case, same size case as the 200 & 400 fixtures.
I recommend testing the M8 and seeing if it fits your needs.
best,
bob