I use two of these for drum overhead mics, and I really like the small footprint and the weighty round base (around 6kgs). I have these at maximum vertical extension and the boom almost fully extended, and with small SDC mics (such as Rode M5, NT5, etc), no stability problems whatsoever. I would also be happy using these with heavier mics, though I would probably add a counterweight sandbag to the boom arm, or place over the base to ensure no toppling over.
In terms of build quality, typical K&M quality, which I find to be good, although I have marked down the "handling" rating by one star for three reasons:
1. The twist-lock on the vertical pole extension can get jammed if over-tightened. I did this once, by accident, and it took a bit of effort to undo it.
2. I'm not a great fan of the lock used for setting the angle of the boom. Looks cheap and tacky, though it does work.
3. I would be happier if there was a locknut to help keep the bottom pole tight on the round base. I found, when moving the stand around the studio, the base could start to come loose. It won't fall off (there are plenty of threads), but the overall stability is reduced if the pole isn't tightened firmly into the base.
Finally, a really minor niggle, I managed to break one of the cable clips. They are a fairly hard, brittle plastic, so take care when removing them or clipping them back onto the poles.
Despite those apparently negative comments, the stand does exactly what I need it to do, works as intended, and is decent quality for the price. I would buy again if I needed to replace it.