personally, i don't think that stereo wakeskis are any better or worse than HOs. it's all just personal preference. the stereo skis are a little longer, so if you're a bigger dude, then they will be a little more stable. they're also flat underfoot, so they are a little more stable if you're a new rider. although, this does make sliding boxes a little more easy because you have that flat part to slide on.
the HOs have a full tip to tail rocker, so they are super squirrelly and harder to ride if you aren't a strong skier. it's also a little harder to slide a box because there isn't a flat part on the ski to lock on to the box. however, they spin a lot easier because they're shorter and the full rocker makes surface turns a little easier to pull off.
really though, it's all just personal preference. i've got HOs. my homie has stereo skis. I've ridden both, and both are solid sticks. if you're a bigger dude, you'll probably want to go with the stereo setup. if you're a little smaller, the HO's are super sick.
i've got a video of a roll to splat on a set of wakeskis in my profile, but I'm too lazy to post it up. check it if interested.