Maybe it's just me and maybe I've been lucky, but I have never had any problems with the VTS system on a Seadoo. Like everything else maintenance is the key. Check the boot on the linkage at least annually if its hard or starting to split, replace it, and don't use hose clamps, I got some electrical type clamps at Graybar, I don't recall what they're called but someone else will.
I would just buy a good used OEM VTS from Nick, the stock one will work just as well, probably better than an aftermarket.
Lou
Added
I'm still not sure what the clamps are called, maybe Waytek, they look like this.
http://www.grainger.com/product/Hose-Clamp-1ENH8?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/1ENU9_AS01?$smthumb$