I've used Thunderbird with GMail for years, using POP, not IMAP.
It works well. However, in the last few months, the GMail Spam filtering service has stopped working with POP. Items marked as Spam in GMail still get downloaded.
Pop can be configured either way, but what I wonder: doesn't this presume you only ever use one client? For me that would not work at all. Unless you sync mail between your clients another way, then I am all ears.
I am pretty sure IMAP can be configured to delete mail from server after sync, and anyway Google has all the time in the world to scan your emails before you delete them.
I learnt this the hard way in the early days of interneting.
Lost all my emails after an IBM hard drive died on me and my email client was using POP to retrieve mail.
It works well. However, in the last few months, the GMail Spam filtering service has stopped working with POP. Items marked as Spam in GMail still get downloaded.
I guess Google wants us to use their web-client.