Ric-  You might be right about the S series.  I'd rather have a flip-up deck.. 
I'm just a home owner, trying to take care of my space. 
  My  Z is a SS TimeCutter 4260.. Which so far I'm very pleased with..  The 42" really can get into tight spots & fly on the open areas,  I was looking at the 5060, but it won't fit into many areas around my house, & eats up too much floor space in my shop, I got 3 bikes, my truck & the Ol's ride..
 I would agree no steering wheel for the Z-Master.
   PS: The only Z Cubs I see around here are the Farmer's, who has a couple older commercial units with lap bars.