UI and compatibility with original physical games is going to be the next battlefield in the FPGA market until hardware comes out that can clearly surpass what we have now. Otherwise, you're just basically getting a choice of casing for a Mister, which has been available for a long time (
VGEsoterica
, please correct me if this is too simplistic of a take on the current market). As user-friendly as the Mister is right now, it's still a geek's thing with a geek's interface.
Analog bet too much on the retro fetishist and collector's side of things, and it's now coming back to bite them in the ass. The Pocket is currently the only unique proposition they have that's really worth it above any alternative, but if Taki Udon really delivers on his promised handheld FPGA, even the Pocket may soon belong to history.
Just get an emulator. It's not an official console. No different than an emulator.
Yes and no. Many of these devices can output to an analog display with a bare minimum of tinkering with menus, which can't be said for emulators running on PC or most emulation devices. And speaking from direct experience, unless you're emulating on PC, setting up an emulation device, especially an Android-based one, requires a lot more time and information than I needed to assemble and get my Mister Pi running.
Sure, with emulators you get many more options.
As for accuracy, it'd be interesting to have side-by-side comparisons between original hardware, FPGA, and emulators. As much as I like
VGEsoterica
's "one hundred percent as you remember it" shtick, an actual A-to-B showdown is long overdue. I remember watching a video briefly showing the same game running on FPGA and emulation and the emulator going out of sync in a matter of seconds, but that's too little.