Stability is hugely subjective, for example leaving a 20/30 tabs open and playing bfbc2 with fraps will surely drain the available RAM, that for someone could be everday usage.
Taking that into account I find that being able to stay stable for scenerio's like that,
decreases your chances of getting any kind of bsod, therefore 'MORE' stability, which
might be overkill to some but desirable for plenty of people.
On that note, those that have passed the blend run at 1600mb are stable for how they run their rig, for example, gaming 24/7 bfbc2 with no problems, however, it
'may' not be stable for high ram usage scenerio's which
could be unlikely for some as they won't be running fraps and have 20/30 tabs open in the background because that's not how they run their rig.
Once you have done a 12hour+ blend whether it be custom or standard blend, I'm pretty sure there won't be a need to run it again and you
might not get a bsod that relates to unstability of your overclock but then again you
might because as you know overclocking and stress testing is not a guarantee.
There will
ALWAYS be different opinons about this whole stability issue.
This is
JUST the stable club, whether you go for, a standard blend or a custom blend
you should be stable for what you use it for, stability is stability for your own use. If standard doesn't work for you, then go ahead and do a custom blend, that's the way I see it.
This is the stable thread, that's means general stability and extreme stability, both are included, however those with 8gb+ should really want to be using custom blend rather than normal blend (1600mb) which not only stresses the RAM and CPU but also the IMC of the chip which is important for stability.
BUT ITS TOTALLY UPTO YOU!!! - I personally recommend custom blend with upto 90% of your available RAM!!!
Info regarding Prime FFT's and the total time it takes to complete, (credit Shad0wfax)
HERE.