Interesting about the v5s. I have three v5s (one 5.0b, two 5.1s). Once all the setup headache is done, they work fine (meaning no restarts or anything). I wonder what is going on with yours. Otherwise, the v6 I have in my PT Pro has been a headache for weeks. All sorts of data corruption issues, header problems, etc. Alex helped me and I found out the newer firmware I was using was unstable. Backdating it actually helped with the corruption issue (so far).
The "squirrel cage", also termed the "rat cage" by some, was phased out in early 1988. The noise wasn't the principal complaint, however. Many felt the fan was responsible for screen interference; this could have also been the result of the horizontal-facing video board (which isn't recommended for the newer fan, either). I have also witnessed this firsthand in SEs, long before the capacitors became the chief concern among SE analog board problems.
All SE/30s left the factory with a blade fan, but it is theoretically possible to put the old analog and video board combination inside an SE/30.
As I recall, Apple offered a fan replacement program for some time for SE owners. It must not have been all that popular, however, as I don't see many 1987 SEs with the newer fans.
Apple used two blade fans in North American SE models. There's a DC Pico Ace 25 and an Elina-Fan. The Elina seems to be the slightest bit quieter. Of course, the real noise factor can be a hard drive. Both the MiniScribe and older Quantum 3.5" drive, usually installed in an SE with a factory hard drive, were notoriously noisy drives. (However, perhaps to compensate, the SE has a speaker which projects better than any compact Mac as a result of placement and front bezel design).