I've been watching Ariel Posen for a long time now, and just had to get his signature slide. Mainly because of two reasons: (1) the balltip end, and (2) the fit. I tried it in a store once and while I didn't purchase it on the spot, it fit just right on my pinky. So I finally bought it.
It's a *great* slide. The quality seems very high, and it does its job nicely. This is honestly the first slide that I could see myself keeping on my finger all throughout a song, even if I just use slide on certain parts. It fits so well. The balltip end is a nice touch, although I use it actively less than I had thought. One thing that it does for sure though, is that I never get "stuck" on lower strings with the end of the slide. That's a nice feature .
Even though I'll give this the highest score, I want to mention that it's not a tool that does it all. When playing acoustic, I found the slide sound to be a bit on the treble-y side of things. Hence, I started looking into ceramic slides for acoustic guitars, and ended up with a very different one (still The Rock Slide though) that sounded fuller - and perhaps a tiny bit more sustain...? So summing things up: I'm using the Ariel Posen slide for electric and the ceramic for acoustic guitar. I love them both.
Recommended!