I find SystemPal to not offer half as much enough information compared to iStat menu, and I also find it a lot less attractive in terms of UI :-).

As for Little Snitch, you should definitely report it, that is not normal. I’ve used LS for more than 5 years and absolutely never ever had it take more than 1% of my CPU. Extremely rarely I’d have the odd program that doesn’t handle well having to wait for a connection that long, but they were poorly written programs, and they’ve not been numerous at all.

LS is a must for OS X and they make sure they don’t take up any more resource than absolutely necessary :-).