I found the Mac/ v11 runtimes to be ditsy, especially wrt backing up. ie, the client would make a copy of the solution folder to an external drive and when they went to overwrite that folder later, there ended up being annoying error messages (and failures) on the runtime engine. Fortunately the clients were easy-going enough to accept the workaround - 'just copy the datafiles, that's the important bit'.
Only yesterday I had to dip into runtimes again, for the first time in a long time. This time I've converted the source solution to v12 (Classic) and used v12 to generate a runtime. Only lightly tested thus far but seems ok. Using v12.02 for now. Don't seem to have any PDF crashes. RT only tested on ML so far. I also need to test it on 10.6 which I'll do later in the week.
But at least there aren't those rotten error messages when backing up any more!