I got the Everdrive N8 for my Famicom back in December. I'd say it's totally worth it. The last time I did a count, only about ~38 games were incompatible and none of them were anything I was interested in playing. There's a list on krikkz's forum. I was thrilled to be able to play Akumajou Densetsu with the extended audio. It's great to play hacks on real hardware, especially all the Mega Man stuff that comes out.
It's too bad that the FC/NES is one of those systems that just rubs me the wrong way. I don't know if it's because I didn't have one until I was 12 years old or that many of the genres were done much better in the following generation, but I have a really hard time getting into it.