I've got one, and I love it.
Is it a real Amiga? No.
Is it more convenient than owning real hardware? Yes.
Games load quicker using WHD Load Hard Disk images, but you can also load ADFs, and they load about the same speed as Amiga floppies.
Though I would say a keyboard is essential to get the best out of it. I found a PC keyboard that is styled very like the A500 keyboard and feels pretty much the same.
The mouse is slightly smaller than the original tank mouse, and is a modern optical (no ball, thank goodness), but it feels similar and works great.
There does seem to be a little bit of input lag though (almost unavoidable with Linux based emulators), which is really only noticable using the mouse pointer.
Probably the best thing is it syncs properly to TV refresh rates, e.g. 50hz PAL/60hz NTSC so scrolling games are smooth, there's no jitter. I've always found that an issue when using PC emulators.
The enclosed gamepad isn't that great but you can use an Xbox controller, or the joysticks from the C64 Maxi/Mini or other retro controllers.
I will probably get the full size replica when it comes out, just so the keyboard is built in, to save some clutter and also make it feel even more authentic.