Prior to SU4, I would get horrible, constant stuttering with rolling cache on. My performance was still poor without it, but much of that constant stutter was alleviated. And I could consistently reproduce it on my end. Others reported the same.
SU4 brought a lot of “stealth” fixes that were network related. It fixed the live weather only on first flight bug. It also fixed the super slow update downloads many people were having. After SU4, I haven’t been able to see a noticeable difference in performance with it enabled or disabled. So based on that, I choose to preserve the write cycles on my SSDs and not use it. I only use manual cache for a few large areas I fly out of often.
And post SU5, I haven’t really tried. The sim runs acceptably well for me now in any case. I still only use manual cache.