My wife and I purchased a 2009 Hobie Oasis tandem kayak with the Mirage pedal drive system towards the end of 2008. Quality problems with the new molds delayed the boats arrival until January, but since that time we've put quite a few outings on the hull.
We purchased the boat primarily with my wife in mind - she wanted to go with me on social kayak outings, but didn't really enjoy paddling, and didn't feel she would have the endurance on her own to stay with the group. Hence, the tandem pedal boat.
The Hobie Oasis is very cleverly designed for a recreational boat - lots of storage, decent seats, very stable, and fun. Plus, Hobie even includes two large water bottles, two paddles (needed for backing up and very shallow areas) and a dry bag! The Mirage drive is a clever system, delivering lots of thrust. We installed the Turbo Fins (Hobie should really do this from the factory), and found a significant increase in performance with very little extra effort (we gained about 1 mph average in cruise speed). With the Mirage drives, the motion is really more like a stair-stepper motion than a bicycle motion, but you'll use a lot of the same muscles. It's pretty similar to peddling a bike up a low incline. The hand-operated rudder is very effective, turning the boat on a dime.
All that stability and those nice touches come at something of a cost - the boat is quite heavy (The hull, without drives and such, is about 69 lbs - you'll need two people to get it on and off the car if you aren't fairly strong) and not particularly sleek. It accelerates almost immediately and easily maintains a decent cruise speed, but really pushing it takes a lot of effort - you're really moving some water! Nevertheless, my wife and a friend's teenage son won a recreational class boat race with our Oasis, averaging just over 5 mph over a 3.6 mile course. We've sprinted the boat to 6.1 mph.
To help with moving the boat, we purchased the Hobie plug-in cart, a two-wheeled frame that plugs into the bottom of the cart. I highly recommend it - it really helps with moving the boat around. We got the cart with the inflatable sand tires that float. You can actually back the boat into the water, then reach under and pull the wheels out from under the boat.
The 2009 model has some significant upgrades over the 2008 model, including a new hull design, much better pull/pull rudder activation system, and new designs for the drive system retaining clips and fin mast installation.
A fun boat, and highly recommended if you want easy cruising, no-hassle fun! You'll find all your friends will want to try it out as well...