Is it just me and my wife? Today, we did a 2nd water test of a 2011 Oasis. The 1st time was 6 months ago. It seems like a great idea but when you actually do it, we were not impressed. Its no easier or better than paddleing, its just different.
I wonder how your Drive is set up and adjusted.
-- It's much easier if your legs can extend fully.
-- The Drive should be easy to move by hand without much friction. If not, the cables are adjusted too tight (yes, they have been known to come from the factory that way). When installed, the Drive needs to be properly inserted into the drivewell.
--If you have ST or ST Turbo fins, your fin adjustment matters.
IMO, these three items make a HUGE difference in the ease, speed and fatigue you and your wife experience. Proper set-up is important -- your dealer should have gone over this with you.
Your seating position can also make a difference. With the Mirage Drive, the seats are normally much more reclined than with paddling so you're not drawing your legs all the way up to your torso.
Finally, if your legs are not used to the movement, it's easy to overdo in the beginning. It doesn't take long to learn to pace yourself though.
If you suspect any of these problems, the forum can help get them straightened out, if not your dealer!