[curt.clifton]

Yes, you can delete versions other than the latest w/o destroying functionality or data.

I believe OmniFocus.app is the latest one. The build codes are added to the names to move them out of the way.

I've been running Sneaky Peeks since the initial 1.0 beta 18 months ago. I've never kept a past version. If a version is seriously bad---I've only seen this once or twice in many 1000s of builds---I've always been able to download an older version from the Sneaky Peek page. (Disclaimer, I haven't tried this on the 1.1 Sneaky Peeks as I haven't had any issues.)