I have a kirby and it was quite frustrating.
After hearing so much from many members that consider the kirby as the very best invention after sliced bread, I was expecting too much from it.
It sucks, great! But i dont thing suction power is everything.
Luckily my kirby was free, otherwise id have returned it.
Its a great vacuum for a spring cleaning, but its heavy, a PITA to move. A PITA to manouver (even with the drive assist), that giant head is a pain because it doesn't fit under furniture, those 363838363649050372 accessories are a pain, the cord is wonderful during use, but a pain to wrap after use. The bag, gosh, that horrible bag. Its huge, you must decide if you throw away a bag that is half full or if you simply continue vacuuming with a stinky bag.
I have hardfloors anyway, so my 16 amp electrolux bagless canister does the job very easily and after done i empty the container in the toilet in 3 seconds.
I use the kirby exclusively to vac the lawn in the balcony. (Artificial, of course)