I ended up buying the older F1, why?
The F1+ was $2199 + $240 in shipping, so $2439. The older F1 was $1,350 with free shipping. The older F1 I could run with a spare HP server power supply I have, the F1+ Id have to buy a $200 or so 1300w PSU, so close to $2,700, so 2x the price for not 2x the hash power. Leaves me enough in pocket for other gear or a future update to the F1+, if and when it comes out. Power usage was similar when evaluating efficiency, but when calculating efficiency along with price efficiency, the F1 won out for me.
The efficiency is definitely the same as the hashing chips (the xilinx fpga) are the same exact modules, it's just that they decided to research new heatsinks and cram three hashboards in single tube miner versus the previous two hashboard and thus the f1+ was born.