That smooth finish from a power stretcher totally changes how you plan the job from the start. Getting the subfloor PERFECTLY clean and flat becomes way more important because the tool shows every little flaw. It turns a brutal physical grind into more of a precision setup, which is HUGE for saving your back on those big spaces. You just can't go back to the old way after seeing how tight and professional it looks.
Spot on about the prep work. Ran into that last week on a big living room install-missed one small hump and it looked awful once stretched. Now I triple-check the floor with a level before even unpacking the stretcher.