We recently bought two Sea Eagle Fast Track 385 inflatable kayaks, and have had a ball with them! As mentioned, they have an inflatable keel, and also incorporate a fixed skeg, so they track beautifully (even in a strong cross wind, or substantial boat wakes/waves).
The high pressure air floor is most sturdy, and provides a strong feel of stability (unlike some dinghies we've experienced over the years).
We also purchased the automatic battery powered air pump which makes inflation a snap! These are sit-on (as opposed to a "sit-in") inflatables and the seats are also inflate. (The seats look a little "goofy", but are very comfortable in use, and provide a comfortable angle for paddling).
Even though these are tandem kayaks, we paddle them as singles, which allows our two 75 pound pups to ride along!
We're not sure how they'll hold up long term, but to date they've been great.
PS They are sort of "pricy" but what cost "fun"?!?