Should be cheaper as renting physical discs. Some in this thread said it's not more expensive as renting but there is a huge difference. When you rent a game the rental service gives you the disc and they can get only money from one person per disc. That's not a problem in this case so that Sony could calculate with much lower prices as rental services can. If a rental service could give one disc to more than one person at once, their prices would be also lower.
I didn't expect much lower prices for a week but one week should be only 5 bucks, the 4 hours option should be a one day option and also cheaper and the 90 days option for 30 bucks sounds to me more like a price they should take for the purchase of the whole game. The 30 days option sounds ok to me.