It's more or less the same as intellisense most of the time, but occasionally it tries to guess an entire multi-line function and it throws me way off

I don't know if it's a matter of just sticking with it to learn like any new tool, or if it is just really not as useful as people say

One thing I've noticed is that with traditional intellisense it was often fast enough to get ahead of me so I could tab complete

Cursor is slower than me. Often I am typing faster than it can think, which makes it suggest things I'm already past.