I personally have not sure one, as I have been lucky enough to have a garage, but most people I know who have used that style have complaints. Some of them are about longevity or duritility, some complain about having to adjust the covering every year. And while I do not know the owners or the story, I have see a couple that have either torn and dropped everything onto the car or, worse yet, actually collapsed onto the car.
Then again, most people around do not spend a lot of money on their enclosures, so your mileage may vary.
If it were me I would want a more durable solution and if I used one it would be a stop gap.
Also 120 PSF snow load? in CA? Are you sure you did not swap the snow load number with the wind speed? Here in Maine, if there were a code, I would have to build to 60 PSF roof snow load and 105 MPH for wind, doubling the roof snow load in CA seems a bit extreme.