There's a lot of factors.....but not having snowbanks that build up over time, or being able to direct where the snow goes independent of travel (push) direction are probably the biggest factors in getting a blower. Especially in tight spaces (around cars, buildings, etc..) where maneuvering gets tricky.
Everybody's situation is different.
Blades are typically, but not always, wider than most blowers and one can quickly cover a lot of ground. But you have to be able to push snow far enough away on the first storm of the season to allow snow banks for the rest of winter's storms. This may mean pushing it off driveways, and across grass (i.e. ripping up the grass) to allow room. Is that a problem? -Sometimes yes, sometime no.
Pushing snow require a vehicle with enough weight and traction (and power) to push the snow (Well that seems obvious!). Remember, angling the blade means you just have more snow to push on your next path. Example: You want a 6' wide path, but you need to push it to the side 12' to leave room for future storms, so you have to push the first 6' to the side, to make a spot for your desired 6' pass coming off the plow, then have to push that another 6' to the side to be at your snow banks. That's 3 passes versus 1 with a snowblower. Now imagine if its a 20' wide path. However, if it's a light (not deep) snow where you can just keep "doubling up" each pass and still have power and traction to push it, that's a lot quicker.
Whereas, a snowblower (and the thing propelling it) only needs enough weight and traction to move itself, and uses engine power independently (of traction) to move the snow. Example: With my little 18hp, 600lb riding mower/snowblower I can continuously drive through and blow a foot of snow to 30' away. With a blade I could go about 3' before too much snow piled up & I ran out of traction.
Snowblowers (and there shear pins don't like rocks); plows don't care, they'll just rip them up, like your lawn when you wander off the driveway.
