I have email accounts on several domains that use Google Mail, and thus far I've only ever used POP to send and receive mail from a single inbox. This is quite functional, and as long as I remember to select the appropriate FROM address when starting a new thread, mostly works without any additional thought: messages received on account A are replied to via account A, and so on.
My only complaint is the lag -- I've seen sometimes as much as a half hour between messages arriving in an inbox before being imported into my primary inbox via POP.
My question is this: Google also supports IMAP. Would that be in any way preferable over POP access? Reduced lag would be nice, but not at a general speed cost, if everything I do has to check another mailbox too.