Abusing their patent portfolio directly, ditto through proxies, continued attempts to subvert open standards, bribery to use Microsoft software in various third world countries (and in Romania too, and Germany for that matter) and many others besides but those alone would be enough to not make me go back to using their development platform.
The anti-trust result put Microsoft under US Federal oversight for 10 years. After 10 years, the Justice Department found Microsoft ignoring requirements they were supposed to supply them and extended that oversight for an additional two years which just ended in 2011.
I mean no disrespect, but what's the bad stuff being done my Microsoft today?