Lobste.rs is alright.. I've taken some dips as a reader and turned down invites.

Ignoring the actual submissions, which are usually mirrored on HN, I find the small user base often doesn't offer much in interesting comments. Many are short with little value, and I don't recall seeing many submission authors piping in, or luminaries with the deep knowledge that you sometimes see drop in on HN.

Friends tell me there is a definite political bias that leaks out.

I think Hackaday is a good alternative for hardware oriented HNers.