I have used my Shark Stratos 4 times.  It is exciting and disgusting to see the amount of dirt that is coming out of my carpet!  Here are what I find to be the pros and cons: Cons - as several people mentioned, the unit is heavy.  It is taking me some time, but I am learning to maneuver the beast.  Because of the larger head and bigger collection canister, it does not go as many places as my old Shark.  Fortunately, it comes with a huge variety of attachments.  The 2 spots designated to hold extra attachments are in such an area that the attachments often get knocked off.
Pros - the suction is AMAZING!  The unit has lots of attachments and comes a part in a variety of ways to get to the places you need to.  The collection canister is big, so I only have to empty it twice instead of 5 times.