I joined an erg spin class at craftsbury last week and it was remarkably fun. I am with you in that I will try to add it in to my gym rotation more.
I think erg biathlon could be motivating - perhaps with a nerf gun for simplicity and minimal safety constraints. Erg is great for intervals at 30+ spm, but this leads to pain. I think sub 26 spm is sustainable, and does a great job strengthening and training legs and core. It's a nice change of pace from ellipticals, e.g.
The trainer at our office gym replaced the elliptical with a second erg. I was pretty surprised, I think of ellipticals as being pretty popular and erging not so much. Plus, most people probably don't really know how to row whereas I'm not sure one can fuck up elliptical technique. (Or maybe it is possible, I don't have a lot of experience there.) This post is not relevant.