i like to stay with on-board tools as long they meet the needs. capturing had to happen uncompressed, otherwise the CPU-load would have been too heavy (playing the VI, capturing the screen and compressing in one run).
there are a series of other applications to be found on the net - some of them also allow uncompressed recording to put minimal load on the CPU.
also osX has a very good screen capture app - not sure now if it also allows uncompressed video, but the mpeg4 codec on macs eats not too much ressources.
christian