I tried MS Outlook (as I had Office installed already). It has some great snooze options in the alarm popups, including options like "remind me tomorrow morning", and it can sync with Apple calendars that are stored on the same Mac, BUT it doesn't work with iCloud-based calendars so there's no syncing across devices. That rules it out for me.
I'm also trialling the new release of BusyCal (2.0.1). It now has its own snoozable alarms as an alternative to Notification Center, apparently introduced in response to this problem that we've been complaining about.
https://support.busymac.com/tickets/14362
From a quick test it seems to work well, syncing dynamically (both ways) with iCloud calendars, and does indeed provide variable snooze (though you have to type the snooze time rather than selecting it from a popup). The Notification Center popups can be turned off in system preferences, leaving you with an experience much like the alarms in Lion, but with more adjustable snooze options. BusyCal is expensive, but it looks like the best solution I've found so far for this annoying problem.