Endo, while you are certainly entitled to your opinion, bear in mind that others may, and in fact, do disagree. All things being equal, I would prefer to have a rotary pump in my home espresso machine. Now, I never would have said that
until I actually had one. Indeed, like you (and many others here), my initial thoughts were along the lines of
how loud can it be or
who cares how loud it is -- it's only on for 20-30 seconds and so on . . . Keeping in mind, I had machines with vibe pumps for nearly 30 years, the noise level of the vibe pump only seemed loud to me
in comparison once I got my rotary -- and now, every time I use my vibe-equipped machine (which I do five days a week; it now resides in my office), I am struck by how loud it is . . .
Also, keep in mind the noise level of the vibe pump in a Rancilio Silvia or Gaggia Classic is indeed quieter than the noise level in many "prosumer" machines (bigger pumps, I suspect).
No difference in the cup. None. But, for lack of a better term, there is the "live with" factor, and pulling 4-5 doubles in the morning can get really, really loud!
BTW, when I had my Gaggia, I too never worried about "if it can produce 100 back-to-back shots without overheating." Friends came over, and I made coffee after dinner using drip or a press pot -- I never turned the Gaggia on. Today, as long as we're a party of 12 or less, I
can make everyone an espresso or cappuccino . . . at least I can offer, which is something I never would have dreamed of doing with a Gaggia/Rancilio home machine . . . .
Cheers,
Jason