That I really couldn’t say, only a few weeks in on emails that were not being used before, so not really getting “unsolicited spam”.

I am getting a lot of messages related changing my accounts over.

Their spam filter is configurable though:

They also have complex filters you can set up to either auto-label, or auto-sort non-spam into folders, from basic usage, up to complex regular expressions; depending on your level of dedication.

All I set up for now is an auto-filter any email with ‘unsubscribe’ somewhere in the body to be sent to an ‘subscriptions’ folder. I will get around to it more eventually.