Ask HN: multi-window SSH client alternative to putty?

I've used putty for years for connecting via SSH. Often I like to have multiple putty windows open, sized, and positioned so that I blanket a third monitor with 5 individual putty windows/sessions. Is there another client which better manages a setup like this?

Hopefully one that: -opens child windows within the parent -can tile child windows -remembers child window positions -remembers passwords

I've tried 'Poderosa' but it's buggy and seems to have fallen by the wayside in terms of active development.

If there are alternatives that fit the bill, that aren't free or open source, I would be interested in those as well...

thanks!