From a working drummer standpoint, the cowbell is the better choice. In fact, I'm a proponent that every drummer who wishes to work as a drummer be issued a cowbell.
The reason I only use a ride, crash and hats is because I also have a cowbell.
Look at it this way: if you go out and play with a band and someone requests "Honky Tonk Woman" - how do you do that without a cowbell? If you're playing for dancers and have to play anything latin, you're gonna need a cowbell. When someone says "More Cowbell" how can you respond to that if you don't have a cowbell? There are far more interesting rhythms to be played if you have a cowbell.
The fact is, and as funny as it sounds, you'll need a cowbell far more than a china cymbal. If you can't give the band what they need to keep working, there's plenty of drummers out there like me who have cowbells and are ready to give it to them. It's like a guitar player with a wah-wah pedal - as overused as it is and cliche'd, fact is, unless you're a star forcing your own music down someone else's throat, you're gonna have to supply the people with what they want to hear.
Besides, why couldn't you get both? A good LP Mambo bell and a hoop mount attachment won't cost you more than $40. However, if you do get both, don't blame me if that china gets played less and less....