We've never needed a high speed rotary. We did ok with an old 15" Taski for a few years, then bought a new 17" Victor because you can load it up to over 70kg, but this is not necessary for most jobs.
We do always use an sx12, but we have got a TM. People always tell us you don't need high pressure, but we use 1,000 to 1,500 psi quite often, and on porties there's a big difference between the pressure showing at zero flow and the pressure achieved with flow through the tool, especially an sx12.