Among living slide players, I rank Derek Trucks right up there with Ry Cooder and Sonny Landreth. His feel is amazing, and his wrist must be made of rubber to move like that.
There are a lot of ways to skin the slide guitar cat, and who's to say one is better than another? When Warren Haynes first joined ABB in the 1990s and was playing the Duane parts opposite Dickey Betts, he used a short open ended metal slide in standard tuning (he's since changed to a Coricidin-style bottle, stuffed with a cotton ball to keep his callouse dry). Jeff Beck and George Harrison use standard tuning, too. Ry Cooder, Billy Gibbons, and Sonny Landreth prefer open G "Spanish" tuning. Skydog, Trucks, and Joe Walsh prefer open E. Different players prefer different fingers, too. Derek and Warren use the ring finger, Ry Cooder and Johnny Winter use the pinky, Billy Gibbons and Joe Walsh use the middle finger. I bet you could find someone using the index finger, too. Slide material is also a grab bag. Medicine bottles, wine bottle necks, ceramic thimbles, brass pipe, wide steel or silver rings, you name it, anything that fits over a finger has probably been used to play slide guitar.
I think the best thing to do is try out some different slides, go with what you find comfortable and pleasing to your ear, on whatever finger works for you, in whatever tuning you find easiest to get around in.