Yeah I've been to key west but I wasn't crazy about it. But Key Largo etc... is awesome for snorkeling/scuba diving.
I've taken two trips down to the keys at this point. The first was an extended weekend in Key West where I saw the tourist stuff and got drunk every night.....Captain Tony's was the best place for me there. The second trip I got a place around Islamorada and used that as a base to explore Key Largo and the other keys.