You are not going to find anything that will out clean a rotary...and the Hoss is the best out there...its ability to flush and get everything that is burred down into the carpet that not even a vacuum cleaner can't remove is amazing...
on the same side of the coin....your not going to find a better tool out there then the zipper...it is a industry changer....and will make its mark for years to come...
you can argue both sides....
I can only tell you what I like...and my Hoss will never see another commercial carpet again....we just finished the school and I used it on the entire job...
It took me lees then a day in a half to do this entire thing.( record time )...one truck running a Hoss and me with the zipper...I cleaned much more area then he did and the carpets came out perfect...you just could not ask for better...it does a excellent job at deep cleaning the CGD...
They just booked that huge Church again for December....
I will have another Zipper for the other truck before I do this church again...
as far as residential carpets..My Hoss is the only thing I will ever use..it gets deep down in the pile of the carpet and flushes everything completely out..I can go over a area with the wand or the zipper and still get a bunch out with the Hoss...
as far as dry time...I have not seen anything out there that will ever beat the zipper......
IMO..both are a must have...but you cant really compare the 2....they are both in a class all by them self's.........