I used it extensively. I obsessively recorded everything off over the air digital TV and wrote it to DVDs. I had a little script to look up ratings of movies in IMDB, apply weighting factors due to personal tastes and record all the ones which made the grade. I'd then edit the commercials out and burn to DVDs all losslessly.
However, this all came to an end when my 2 year old son took the running hosepipe from the garden one summer, through the open patio doors into the house and proceeded to fill up the MythTV computer with water (along with the TV, VCR, DVD player and sofa!).
I never quite had the heart to resurrect the system after that and it was an end to my MythTV obsession. It was fun while it lasted.