fragonard: ... By stability, I mean frequent crashing, ...
Sounds like an Oblivion problem indeed (and you'll very likely encounter this type of problem with your GOG installation, too, sooner or later). Some of the crashes are caused by memory (mis-) management, some by mod incompatibilities (not Oblivion's fault most of the time), some by a number of other reasons.
My personal experience is that the crashes appear rarely during the first hour of a session, and that the probability of crashes rises beyond the first hour (which is why I'm hit almost never - my sessions rarely last longer than an hour). As a consequence, I save often.
By the way, when I'm to mention one particular situation where crashes are most frequent (but still rare) according to my experience, then it's cell changes, for example when going through doors, or when crossing from one region into the next (not always easily recognisable while playing).
If you encounter such crashes during the first hour not only occasionally but frequently and reliably, of if a particular crash is reproduceable, it might be worth considering other explanations.