There is nothing wrong with a good RPC.
I have recently added another 4kw/5hp idler motor to my home made unit so it is now a 10hp RPC. I get varations of less than 2% measured phase to phase when this unit is loaded with up to 5hp, which is the largest motor in my workshop.

My neighbour gets variations of up to 6% in his workshop which is supplied by the power companies generators. I guess this variation is caused when an exceptional load is placed on one of the phases to another neighbours home, when they start a large load item such as aircon etc.

Theoretically, If there is significant drop in my single phase power, voltage will drop over all three phases.

In my neighbours case, the low voltage is usually over 1 of the three phases, which is an inbalance that will surely have an effect on the "sensitive equipment" as eluded to above.

I guess what I am saying is this..... Its all horses for courses. If I were able to have 3~ connected at my workshop for a reasonable cost, I would have done it. That not being the case, the RPC was and is a fantastic option for me, as I can run all machines, and I have learn't a great deal in the process. I did have to upgrade my single ~ power to my sub main in the worksop though, but this was an easy exercise. I had the conduit in as existing, and I simply used the existing 4mm2 cable to pull in the new 10mm2 cable. My BIL hooked up the business ends, and I was good to go with the pase converter stuff, which he (sparky) didn't want to know about.