We have the Circuiteer II which is the exact same thing as the K9II but is marketed to show livestock (like Llamas).
It takes me around 2 hrs to dry Cole fully. Molly, at least 2.5 hrs. I've found that if I dry for about an hour then wait 30 mins, ours will be soaked again. The water seems to seep out of the hair shafts and they're actually WET again. It takes a few "sessions" (within one long session) to get them dry. Even when I get them back from the Groomer, they need to be dried for about 30 more minutes. They'll actually leave wet spots on the floor. And they've been being blown out for a good 2 hrs there with big commercial dryers.
Debra, I think the dogs that dry in an hour or less, don't have as much coat. Mira can dry fully in about 45 mins to an hour, because she doesn't have a ton of coat. Cole has more coat on his front legs than she has on her torso. Chance takes about an hour and a half. Syd is big, but he's not heavily coated. Addie takes FOREVER. LOL
I believe the K9III is the most powerful, but it's BIG. The K9II isn't small...kind of reminds me of an old model Electrolux vacuum cleaner.
I have a small Metro dryer, but it takes 30 minutes just to dry Cole's feet with that. And they're not all that wet! Small/portable is virtually worthless except for some touch up blowing out. Our handler uses that before going into the ring to fluff and puff.
Go with either the K9II (or equivalent Metro Air Force Master Blaster) or the K9 III. You'll be glad you did.