I like mine and won't return them; they work well. I think it's important to keep in mind what they do and don't do, though.
For a lot of us (depending on where we live and what salons we go to) we'd pay as much for this one-time style done professionally as we do for the tools to do the same style on our own time, anytime we want. That makes them worth it for me.
As for keeping the curls, I've found magnetic rollers turned vertically work very, very well. It won't preserve the same perfection you get the first day, but it definitely keeps the general look going strong all week. My hair has good "memory" and I find after a week of wearing spirals my hair will continue an inclination to curl in that direction even after a wash and regular set with plastic rollers.
I've never thought spirals were meant to function the same as a regular rollerset--rod sets, curlformers... those styles are just not as durable or flexible as a regular rollerset so I didn't expect anything other than what I got with them--and I get endless compliments everytime I style with them, so it's working for me. I'm OK with they do and don't do, and I love my CFs!