I've been told, and confirmed, that the play needed to get your room comped is 800 points/day on video poker and 600 on slots.i verified that your points/comp balance wouldn't be used for that.
So, 800 points requires $6400 coin-in if you play JOB. I consider this barely achievable at .25 in one day. If you escalate to $1 DB, you need $12,800 per day (points earned are at half the rate of JOB), which would take you half as long as earning the needed amount at .25 JOB.
Now, assuming what I was told is correct, you earn 0.9125% in comps and cash back at JOB, or half that at DB. So you have a net earn of about 0.45% on either game. The real question is whether you can more easily stomach the high variance and greater coin-in of DB or the mind-numbing boredom of JOB.
You'll be eating at Magnolia's, and you'll be downtown, so breaking rocks at JOB might be worth it.