We're on the bleeding edge and using phab very actively, so thought I'd share feedback from our director of engineering:

"you don't know how much of a pain in the arse is to work in Phab without preview and with that tiny space for writing tasks.... big step back."

I tend to agree. For formatting, having the preview has been really useful, so it does feel like a step back. Just sharing our feedback!

Cheers,
Dave