GK,
No, no problems at all. My desk sits in the corner of a room with a north-facing window on the left hand side, so my monitor (and TIR cam) faces into the room. During the day the this part of the house is reasonably bright, although without direct sunlight, and TIR works without issue. At night the room light is behind me (although I use one of those energy saving bulbs, so it's not all that bright) and again TIR works as normal. I don't know how it would perform in a room with direct sunlight, but it seems to work OK here. I use a TrackClip Pro for preference, but I've tried it with the hat clip, and it works OK, but I have to dial up the sensitivity which I guess might cause problems in a brightly lit room.
Jabo