I use an Orbitec Brute 17" OP with John G's grout brush. Varying length bristles get into grout lines fairly well, but still use a pole brush. Made an effective sling ring from vinyl baseboard. Sometimes strap on one or two 12" sections of railroad rail for weight. Probably easier to handle on a slick floor than a 175.
I'm assuming that some level of additional pole work will always be likely to encounter most of the time.
Any advantage that can be of benefit by mechanically scrubbing to cut down the amount of manual pole work is better.
Some of the same established arguments to support whether either motion is more effective when cleaning carpets when comparing an oscillating machine and a rotary should similarly apply here.
Is the physical contact between the bristles and the grout more effective if it is in a slower, multi-directional orbital movement, as opposed to a faster rotation in only one direction?
I would think logic would favor an orbital motion, but unless this translates into a calculable difference, it's probably not worth pursuing.
Who here has scrubbed T/G with BOTH?