I haven't experienced it with this car...yet. Oil consumption is very low. Surprisingly low, in fact. I have had Toyotas since 1974 and was always wondering where the heck the oil was going, VVT or not!
Mine currently has 80,000 miles on it, and oil loss does not start until a bit over 100,000. The biggest loss of oil comes from the valve stem seals. If the car sits for more than a day or two you get a puff of blue out of the tailpipe.
And I have used MMO for a long, long time, never had sludging issues. I used to use Catrol GTX, but after having an old (89) Mazda found that Quaker State High Mileage was better. The only thing I did after the oil loss started was, check the oil more often and add as needed! 244,000 on one Corolla, 258,000 on the GTS. The only reason I stopped running the two Corollas when the mileage got that high was because the bodies were rotting out!