I've used them, they install nicely, actually even easier than tantalums because they conduct heat nicely and the solder flows easily. They're smaller too so it's easier to get at both sides with an iron to install them in tight places. An added perk is they are non-polarized so you don't have to worry about getting them the right way around. As I mentioned, the only reason I haven't used them widely is cost, in most cases the cheaper tantalum caps are more than good enough. If you don't mind spending a bit more, by all means give the ceramic caps a go, they're very good.