I've not had experience the Elf stuff specifically, but I've had some of their not-Empire and character models in the past. On the whole, they're pretty damn nice for the price; most of the detail is very sharp, they fit together well and are a very good match for the classic Warhammer aesthetic. One caveat is that they are sculpted by hand rather than digitally, so some parts are not 100% symmetrical or smooth. I don't mind this so much as that's not really visible once painted, but something to keep in mind, perhaps. I'd still recommend them, though, especially at their very reasonable prices.
Here's a scale shot of some of their stuff, which did seem to vary a bit (the men were a bit bulkier and taller than the Elf). From left to right, MOM Elf Prince,
GW Sister of Averlorn, MOM halberdier,
GW Empire handgunner, MOM War Priest.