You are correct, "Delete" and "Delete All" will commit changes to the parent/base disk, whereas "Revert" and "Go To" are used to return to a previous state. "Delete All" will commit all snapshots in the chain, independent on whether they show up in the Snapshot Manager or not. "Consolidate" was introduced with ESXi 5 and basically does the same thing as "Delete All", except that you don't need to take an additional snapshot in case no snapshot shows up in the Snapshot Manager (for more details see http://blogs.vmware.com/vsphere/2011/08/consolidate-snapshots.html).
André