Vacuum Cleaners Discussions

My wife and I have owned about 10 vacuums in 20 years.  The first 5 were yardsale, then a Dirt Devil, then a Hoover, then an older Electrolux which worked awesome untill it caught on fire, then a Kenmore, then another Kenmore, then I got fed up and installed central vac.  NOW WE'RE TALKIN!

Well, she made me move and central vac would ba a real pita to install and it aint gonna happen. A friend of ours gave us a Kriby G5 (yeah, she hated it so much she gave it away) but its too much of a pain because we're 50/50 hardwood+tile and rug.  We currently own another $200 Kenmore, which I don't understand why they stink so bad now because my mom had the same one for about 20 years.  Now my mom has owned a Miele for about 10 and its still good as new.  I just can get past the $1200.

Is there a huge difference between the $1200 Miele Capricorn and the $700 Miele Pisces?  What about electrolux? Our house is 3 floors and about 4000+sqft.  I want a fast vacuum.