I’ve used all the choices at one time, including “other”, but at the moment am using H264 for blu ray and ProCoder for mpeg2.
BD-Rebuilder is working ok for me using the X264 encoder, though my machine is only marginally fast enough for high def encoding.
ProCoder is simple to use, accepts everything I’ve thrown at it (though I’ve had to use AviSynth a few times on some .mkv files), and its already paid for…might as well get some use out of it. Quality is excellent when reencoding dvds via DVDRebuilder.
If I were just starting out with mpeg2 encoding though, I’d just use HCenc. It is a very fine mpeg2 encoder considering the fact that it is free to use.