I applied to Harvard's ROML department for a dual-track PhD in French and Spanish. I've really only heard good things about the faculty; people tell me they're great to work with, approachable, (etc.). I guess it depends on who you ask. I was debating between applying to the Comp. Lit. department and the Romance department, and chose the latter because, from what I hear, it's also a lot more liberal in terms of the work it does and the program structure. As far as rankings go, I haven't come across a specific ranking listing Romance Language departments, though I do know that Harvard has some pretty well-known people (Diana Sorensen, Doris Sommer, Brad Epps, Susan Suleiman, etc.)