I bought one this past weekend, (live about 125 miles from the store), first 3/4 inch nut I tried to grind off, it started smoking, before I could get the switch turned off, it melted and couldn't turn it off. Later, when I plugged it in to see if it would still work, it started smoking, filled the pole barn with acrid smoke.
All motors when built, have built in smoke. It's just that the chi-com motors smoke earlier...
The only power tool I've had any luck with is a rotary impact drill I bought about 5 years ago to drill some 1" holes in concrete. ALL (emphisis on every one) the rest have died a rapid death in the first couple of hours of use.
Other tools seem to be OK, but I'm swearing off the electrical power tools after this one. I think that's about 5 or 6 times I've tried.
Try drilling a 1" hole in concrete with a star chisel and a 5 pound drilling hammer and you'll be back to being a power tool junkie.....
Home Depot has a Milwaukee 4 1/2 inch angle grinder for $59 that's guaranteed for 5 years. I've got to finish grinding those nuts, so I'm headed to HD today.