I bought an m-6 and an m-8. The m-8 is better balanced and seems less noisy than the m-6. Both are still impressive overall. Longevity and tolerance to overheating are untested at this point. Update: After further observation, I can see that the m-6 was dropped or subject to a similar hard impact prior to arrival, perhaps in the factory, perhaps by Amazon. I'd say that is why its legs are bent, and probably why it is louder, slightly unbalanced, and sounds like a bearing has issues. At first, I thought the bent legs were part of the design, because both were evenly bent, but the m-8 has straight legs, is well balanced, and runs quietly... lesson learned. Had I bought only one, I would have just thought that's how they all are, ha!