Went for a test ride in a SX230 HO (320 HP) Yamaha this past Saturday at HK Powersports in Laconia (
http://www.hkplaconia.com/). I have not done business with these folks in the past. They did have one new one (red) and one demo left plus at least one 210. My wife and I liked the 230 cockpit layout very much and it handled fine. Forward/reverse and throttles are independent so you can actually spin it around in place. It did seem to be noisier that my 25' I/O and the top speed was slightly less than mine which has a 300 MPI Mercruiser and is about 1700 lbs heavier. Low speed maneuverability does seem to be an issue since the sales person who took us out crashed into the dock when we came back

.
Here's a link to the Yamaha jet boat forum that lists the 230 series issues:
http://yamahajetboaters.com/forum/viewtopic.php?t=3199
Bill V