rosin vs bho yield

I'd have to second that, but with only an educated guess. You can also consider that rosin can/has to be done in small batches, basically one nug at a time. I couldn't imagine anyone bothering to set up, blast, and purge an eighth of bud. Just like cost vs reward there... That said, you want lots of oil from a lot of trim/bud, a hair iron ain't gonna cut it.
I've tried the rosin method and had decent success. A serious bonus is you can (if you're on a budget with shoddy connections like I am) smoke the pressed bud. Makes for a nice calming j that's not going to leave me ripped before my shift.

 

I know that with bho you typically get about a 15-20% yield, and with rosin when you use buds, you generally manage a 12-15% yield. This really depends on your method and quality of product to begin with though. I make rosin out of my kief at the end of every 1/2 oz. or so. Your rosin yields are higher if you use something like kief or dry sift, especially if you freeze it. My last batch, I took the kief I got from about 7g of herb, (didn't weigh it, should've). Probably about 1g-1 1/2g of kief, did NOT freeze it, and wound up with a .28g ball of rosin. Not too bad! Especially when you consider how little of a dab you need to get a good hit; it's really quite efficient. I don't really recommend the rosin technique with nugs, but with powdered concentrates, it's fantastic.