It starts up for me in under a second on my M4 mac. (Obviously could be faster, but doesn't bother me personally on my hardware)
My one main "issue" is with using the pi-sandbox extension. It's based on a forked claude code sandbox runtime. Not exactly sure why a fork was needed, and the fork is a bit behind now. I also wish the sandbox feature worked a bit more like how Cursor's sandboxing worked. Not familiar with Claude Code sandboxing, so can't compare that. I describe the issue and a (slightly hacky, but productive enough) workaround here: https://github.com/carderne/pi-sandbox/issues/50
Obviously the fact that I can fork a plugin for pi and customize it as needed is quite a plus too. Really all the other features work quite well for me!