Thanks for the roundup - real useful info here - and no conclusion or awards necessary - you're simply giving us some good information to make a buying decision, and I like that.
I can personally attest to the MSI Gaming R9 270X. While MSI stretches this year's Twin Frozer a little too far all the way up to the R9 290X, the R9 270X thru 280X are right in the sweet spot of this cooler's capabilities.
I have the MSI 270X in a Silverstone SG05 for one of the family gaming PCs. I picked it up in December for $200 on Newegg. When it's not used for gaming, it is scrypt mining for a little extra cash for the boys. Overclocked and with a slightly tweaked fan profile, it pulls in 400-425KH/s and stays at 70C at 50% fan RPM, and the tonal quality is also very good with the larger fan blades.
Currently at $250 on Newegg, it's a little steep unless you want to mine on the side for a little ongoing cash rebate on the card. The $200 that I paid was definitely a bargain, but I think the card is worth $220-230 based on gaming, cooling performance and overall quality.