I will start by agreeing with Ancestry that even the best programs crash from time to time. Reunion 10 crashes on me from time to time.
FTM2008 onwards over on the Windows platform have had issues with speed and crashing from the beginning. It is probably reasonable to ascribe a large proportion of these problems to file size and keeping the program running too long. I have no problem, however, saying that I would not expect someone who has fewer than say 15,000 individuals to run into these problems.I do though think it is reasonable for those to want to publish the fact that they do not have problems to put their experiences into context.
Switching to FTMM, it was initially said that it was being created from the bottom up. When it actually emerged, it was a program essentially using the Windows .Net code and working on Macs solely because it used a cross platform runtime library called Mono which had known serious problems with memory management problems, and despite being unable to run on older 32bit only Macs was not compiled as a 64 bit program allowing it to address more memory.
It quickly became apparent to me that not only did it have the problems that I had experienced with the Windows version, but they were worse. It quickly grabbed large amounts of memory so that in less, often considerably less, than hour it simply seized up. A simple task such as bringing up the search dialogue took four minutes. Tasks suck as exporting a gedcom or compacting were impossible and the file had to be coverted to Windows format and these tasks done on a Windows machine.
What, however, sets the Mac version apart from the Windows version is that problems seem to hit users other than those with large files, but purely at random, and I wonder whether I can be as confident in assuring potential users that the prime victims are large file owners like me, as I am with the Windows version