I got that notion Pan' . . . after some research I agree . . . they seem ok if one just wants to hook up speakers rather than putting up with the internal set up but that's as far as it goes. It is a quick and fast easy set up but as Eriksimon pointed out, the hook up is only 16 bit which is another black mark. Fine I guess for general sound but not great for mixing and mastering.
At the low end of the price range, nothing is perfect right, one has to give something up to stay in budget. I have read so many reviews and there's always a down side to each given model or product - hence - mine field right - and if you got USB monitors - you can't hook them up to most if not all of the Audio Interfaces - as pointed out to me by Native Staff last night.
In my case I am still on the learning curve and 3 years after starting to record tracks . . . I am finally getting to the stage where trials and demo tracks have finally started to become reasonable edits and now I have to start thinking about the mixing and mastering stages . . . I want some semi-decent monitors to develop my experience and learn from for now - just something to kick start the process and then maybe in a year when reasonable edits have become fully developed tracks I will have worked with the Monitors and got a grasp of it all . . . I can always sell them on then and buy decent fully fledged monitors to mix and master the final cuts for release. I'd love to have £2,000.00 monitors but it's just not worth it for me yet. Still got too much to learn to make it worthwhile for now. If I have to settle for O.K but not perfect . . . that's fine with me.
best wishes
p.s - * in fairness to Alesis - the Not USB versions got good reviews from Sound on Sound magazine
M1 Active MkII review and M1 Active 620 and 520's
links may be useful for others who pick up on this thread . . . people are always asking questions about monitors - i have noticed that