I love me some slide stuff. I only use brass, but that's because I like the weight.
I've been doing a lot of work, mostly on acoustics - which works easier because of the higher actions and heavier strings (at least on my rig), so it's not so easy to "fret out" with. I play quite a bit in standard tuning, but it all depends on the song. In open tunings, I mostly work in open g, but that's just because I'm lazy, and it lets you keep the guitar mostly tuned standard - and you can cheat some open chords that way.