Jetslide JSB-10 Brass 66

This is a great way to play slide guitar.

I play guitar and sing in a three-piece rock band, and need to use slide occasionally in various songs - often with guitars in standard tuning. The normal bars and bottle necks make it harder to play normal guitar parts, and are best used in open tunings. When singing, it's harder to change from a standard slide.
Whereas the Jetslide can be used quickly, and when not in use allows all fingers to be used normally. It's also more like a steel guitar bar than a tube, so it's thicker and to my ear, makes a fuller sound.
It's also easily adjusted for ring size. I found it needs to be slightly loose.
No drawbacks in my experience.