REALLY glad to hear about your G4
Steve: My FIRST Kirby was a G4. I LOVE that vacuum. Very happy that you found it at such a good price! She cleaned up mighty fine as well!
One feature that I've noticed is that when lowering the nozzle, and you hear when the brush makes contact with the carpet - it's just right, no "guess work"; with my older models, I have to keep listening for that "contact point", or judge by the effort it takes to push it along.
The TECH-DRIVE feature is great. In fact, my G4 is on "permanent loan" to an aunt of mine who's balance is a little off from having been on the bad end of a "hit and run" car accident. She still wanted to use a Kirby, but her model (a Heritage II, I think) was getting a little too much for her. The G4, while I HATED parting with it, has done the trick for her.
Very happy to hear everyone having had a good experience with this machine...I've wondered why it rarely gets a mention in the forums.
By the way -- before I passed on the G4, I called the Kirby parts toll free number (1-800-437-7170) to order a new brush roll - just so Molly wouldn't be "inheriting" my dirt. The new brush roll style DOES seem to have stiffer bristles - plus, it has a set of "tufts" on either side of the brush roll to get better side cleaning (closer to the walls, etc.) than was originally available.
I'm really glad to read that you (and the others) have enjoyed using this vacuum. CONGRATULATIONS!