When I receive a phone call on my Newman N2 with MIUI 3.9.20, and I pick it up by moving the slider to the right, very often the screen freezes and nothing happens. Sometimes, the phone conversation starts after a few seconds, sometimes it won't start at all and I get a "missed call" notification. This is quite problematic. On the vondroid.com forum, I saw that more people have the same problem with MIUI on the N2.