yup, fill the cat.  I went as a perk through work (i've worked at island lake lodge the last summer and winter, and lived with the lead guide who has worked in the industry for 10 years) The morning was spent dealing with punters, the afternoon had decent skiers and we hit some alright terrain.  It's generally more about skiing pow then about sick lines.  If you want sick lines, figure the backcountry out on your own.  For like 10ish runs of the best bottomless pow then cat is the way to go.
They always ask about skiing ability, so you shouldn't end up with total punters mixed in with experts.  But keep in mind, that an 'expert' is often a rich guy who skis 5 times a year (but for 20 years...) with an ego too big to put anything less then expert.  And if you end up in a cat with a bunch that came as a group...they'll basically all agree on the same rating so they all get in the same cat. If someone is blatently terrible though, they may ask him to switch cats. But if he doesn't want to, or his friends don't mind..then you're stuck with him.
The bottom line:  Cat skiing is the poor mans heli.  Unless you can find a cat ski company that GUARANTEES vertical (do they even exist???), then you're not guaranteed to be getting 10 or 12 runs (depends on how long the runs are too, these are compared to island lake..)..you could end up with 8 or 9 or (worst case) less and possibly on easy terrain.  Or, get friends and fill a cat.  It is a good way to get a lot of 'backcountry' pow in a day with the bonus of a guide for safety (and they can tell you where you can safetly huck yourself).
Personally...i'd save my money and go ski touring...or maybe get a last minute discount on a low end company for the experience, even then...ski touring with friends is more fun.