Instruct: Classify a review into positive or negative sentiment.
Query: Great hammerdrill except for one crucial design flaw

I was at first very happy with this hammerdrill. It's well built and comes with a case & two batteries. It also has a little clip on the handle to hold a screwdriver bit - brilliant. But when I started to drill into concrete the problems began. It drilled the holes as well as the Milwaukee I had borrowed from a friend, but apparently it has a design flaw that allows concrete dust to get inside and cause the speed control mechanism to get stuck. So when I tried to switch between the two speed settings, I wasn't able to push the switch "all the way" in either direction. That meant the chuck couldn't "get in gear" which means the motor turns but the chuck doesn't. So now the drill is totally useless. It's really too bad because I know Bosch makes great tools...