There are basically 3 buckets of enthusiasts (I know, because I fall into across two of them).
1) Retro-nostalgia game geeks, mostly from Europe but some in North America as well, just vastly fewer. The Amiga sold better in Europe than comparable consoles like the SNES, Genesis, etc. I compare it to consoles because that really is what the Amiga offered to most folks - console quality games in the guise of a computer. Disks (lots of disks) versus cartridges. And some hand-wavy productivity stuff, like the C64 did (it's OK mom, this is a computer and will make Jonny better at school!), that a few folks used.
2) Antiquated video toaster tinkerers and hardware geeks. These folks like to play with hardware, especially antiquated hardware, and see how far they can push it for the novelty of it all.
3) Old Amiga OSes vs Amiga OS 4+. I think Amiga 4 is really for the folks who want to turn the brand into something usable and modern, but in all honesty, I think Amiga - if it were to ever rise from the ashes - would need a complete reboot much like OS X was compared to OS 9 and earlier. OS X was a total rework, and allowed some backwards compatibility for a little while but ultimately divorced itself from the old days. This is the only way it could ever succeed. Amiga (and, ultimately, Commodore) will always be thought of fondly by past customers, but to get a new market Amiga/Commodore would need to reboot. That's my opinion, anyway. And focus on innovation. The brands are currently zombie brands, owned by various firms that simply license the logos to any Tom, Dick and Harry that want to slap it on a Chinese mobile phone, toaster, teapot, whatever. Those days would have to stop.
I personally started in bucket #2 above. I own a never used/never sold Amiga 1200. And as soon as I got it, I cracked it open and installed an accelerator board (they are easily purchased from Amigakit in England) that pushed its RAM from 2MB up to a whopping 9MB. I also installed a 4GB compact flash hard drive (the original never-used hard drive was a dead brick, naturally). As a result, I can load virtually anything I want onto the machine and use it relatively quickly (see bucket 1). Currently I'm on Level 3 of Eye of the Beholder. :) Yes, I deal with PAL vs NTSC issues at times, among other things, but overall it's a pretty nifty setup. Next year I plan to get it on my Wi-Fi - because.
So, from a hobbyist standpoint, it's quite a lot of fun. And it's vastly more enjoyable than an emulator. But it's not for everyone. And my pipe dream about a renewed Amiga/Commodore brand is really, frankly, never going to happen. If a company could create a vision like I described, they wouldn't anchor it to a dead zombie brand (that I love).