I'm a blaster, brojam. The results I've heard, and tried, friends get with personal smashers is not good. I am not a fan of even company rosin. It burns like hash, which I like, but does not burn in, and gunks up my banger. My personal opinion is pressed rosin is a gimmick. If for nothing more than telling people rosin is resin.
Do not use the 'P' word. Purity is an ambiguous term because it can mean purity on different levels. There is no residual butane in rosin, but there may be in resin. Rosin burns, resin boils away and leaves very little residue because rosin has plant matter.
One thing I'll give rosin over resin is the high is more heady like hash and weed.
Alas, I have spent a small amount of time with my buds. They will all get ground up and blasted to become powdered weed. Daggum if I can't help myself from trimming several ounces of my best. Suuuuper hairy! Gimme tomorrow when I turn my tent light on and I'll get a few XXX posted.