G'Day Lisa,
I almost suggested you consider the tandems after reading your revo/adv post. It's great to see you are thoroughly researching this so you can make an informed purchase!
Our first Hobie was an Oasis and if I could only have one Hobie it would still be the Oasis. As RR reports it is very versatile. If you are under 6' you should have no problems with fit. Don't be put off by the bulkiness of the hull. With two pedalers this kayak gets along nicely. We tour with friends with who have much longer sleeker sit in kayaks (the double on the right of the pic is over 7 metres long) and though they may be quicker at the start, by the end of the day we are usually first back to the boat ramp. If battling a headwind or strong current/chop it’s a no contest –the mirage drive is superior!
I note you already have a paddle tandem. Being wider neither of the tandems is a great paddler but I would recommend the Oasis over the wider shorter Outfitter. Hobie will at some stage, I hope, release a tandem AI (latest release date is possibly next January) but I wouldn't hold my breath. It's been talked about since the AI first came out but to hold off on a purchase because it may come out would mean missing out on adventures you could already be having.
You really should demo all the models before making a final choice. Try and organise one with your dealer.
The Adventure is the best for paddling but the Oasis makes a great tourer, can carry a heap of gear and with two pedaling is capable of covering large distances. We usually arrive at our destination feeling much less tired than our paddling friends!