I'm a dry-sift kief kind of guy-- it's what I fuck with daily. Everything else on the poll I've only had a few experiences with.
Now if I only had the patience to do enough sifting to get some full-melt, that'd be fucking wonderful.... I didn't even know it was possible until I saw a thread on here about it in the past week or so.
I'm in the UK, the only hash I've seen here has been imported from Afghanistan, Pakistan, India, Nepal, Lebanon, Morocco etc I've never come across home made BHO or Bubble or all this other fancy stuff!
The equipment used is like an industrial size hair straightener. If you get a hair straightener that has adjustable heat settings or know how to mod one with a rheostat then you're set. Heat and pressure is all it takes to get awesome full melt solvent free hash.
Not if it's done correctly. It's not as high yield as BHO but getting 4* or better melt out of good material doesn't seem to be super difficult. You just have to care about your product--and keep in mind that a lot of "desirable" strains don't melt--no OGs, no straight Haze, etc... That's why you see a lot of Sour D melt.
I had to vote BHO just because of cost and overall bang for your buck. In a regulated market you don't really have to worry about PPM so I'm not so concerned about contamination or hydrocarbon extraction imo.
Sure, I'd smoke only melt, rosin, and dry sift if I could, and maybe I could if I lived in Humboldt, but trying to do it in SoCal without spending $1000+/month retail is not really feasible.
Without quoting prices I'll put it this way--I can get nug run BHO for 4-6x the price of flowers per gram, but good melt is more like 8-12x. (which is reasonable because that's about how much material it takes to produce--with a slight allowance for wholesale differences in prices)