Somewhat lost in this debate is what constitutes 'sprawl' and what type of sprawl is worse than others. It depends on who you ask.
For an ecologist, exurban sprawl like Atlanta or Boston is considered preferable to Toronto. Characterized by extremely low densities (in outer Atlanta, some areas might as well have the density of Muskoka), interspersed with woodlots and lakes and with little of the area actually paved or occupied by built infrastructure, wildlife corridors can still exist in regions like these. In contrast, the treeless landscape of a townhouse development in North Markham with a high amount of paved surfaces is more or less the death of whatever ecosystem existed there before.
From a city management perspective, Toronto's sprawl with its relatively dense, non-leapfrog development is preferable to pretty much anything else because it doesn't necessitate the construction of enormous amounts of physical infrastructure. Building water and sewer mains in Atlanta, for example, must be very cost prohibitive (all other things being equal) because you have to lay a lot of pipe (to use a funny term) to service fewer taxpayers.
From a food systems perspective, Toronto's sprawl onto high quality farmland is not encouraging, but probably better than sprawl in the Bay Area which encroaches on extremely valuable farmland. In areas where a high value crop is grown, such as vineyards, sprawl tends to be much more tightly reined in. On the other hand, sprawl in a city like Calgary or Las Vegas doesn't matter to an agricultural expert, because these are not food producing regions; sprawl in Calgary encroaches on marginal ranchland and sprawl in Las Vegas spills out into a desert that has never been farmed. From an ag POV, I imagine that sprawl in the Lower Mainland is just as bad, if not worse, than sprawl in the GTA.
And these are just differing perspectives from a disciplinary point of view. We should also take into account the points of view of different people who live amidst this sprawl, including people of different income groups, cultural groups, business needs, etc.
Throw all these societal factors into the mix, and what constitutes "bad" sprawl becomes very difficult to characterize.