Now that SSP is SMP, I’m sure it’s pretty glitchy in both. None of the designs I’ve seen have been reliable always. There’s quite a few designs, though. I like the caterpillar ones aesthetically, but the zipper ones go up much faster (though now way down fast except falling). The piston tape design Coder and I worked on was pretty cool in earlier versions of Minecraft, but I guess you fall through blocks way too easily in 1.2.5. It’s probably even worse in 1.3, if anything.
Every once in a while I consider adding a lift plugin. With piston elevators being so glitchy, maybe it’d be a good idea. I just like to avoid physical plugins like that if I can, and keep them as intuitive and immersive if possible. Ladders are almost the same thing, too.