For a large room, like your 6 meter one, I would go for the one with better high SPL handling. In this case it would be the Revels.
Considering the price of F228be and availability of F208, I think F208 is fine deal just like the 2750 Mofi.
Mofi has lower woofer XO point and coaxial driver, making it suitable for smaller rooms. Revels have vertical directives errors, since they are typical loudspeaker with TMW design, but the distortions at 96dBSPL/1m seems a bit better to my eyes.
But my little concerns on Revels, is that they are having quality control issues with their tweeter drivers in S.Korea recently. It is small market with limited consumers so I won't say it applies globally.
My Salon2 had one tweeter with HD problem. Ordered a pair, but both replacement had 2nd HD peak and I'm waiting for another pair.
One of my F228be tweeter had abnormal HD. Changed the driver, had the same problem, so I had to change the driver and the passive XO filter.
A member of the Korean community had a tweeter driver with 1.5dB less output. The dealer offered an driver exchange, but the replacement had excessive HD and is currently waiting for new one.
And Revel is not cooperative with their after service. Had to email and make phone calls several times with the dealer 'cause of such high failure rate in Korea, Revel was suspicious whether consumers were lying for extra drivers...
So do I recommend the Revel or not?
I recommend it. But just be ready and know you're not the only one, if you face such problems...