I do not buy non oem blades and I have read on other sites that the generics are not as strong nor do they hold up like the Deere blades, but the generic blades most favored are the G6 blades.
I mow between 10 to 12 acres per week and now the grass we have sown is coming up finally it is pretty much 12 acres and could be a little more than that now and I do not have to sharpen my blades but once per month "I only use a ceramic wheel on my 4" metabo and really just have to polish, remove a burr here or there, and sometimes a nick or two".
Yes I hit all kinds of small sticks and limbs from the trees and my JD just mulches them to nothing and rolls on.
Here is a link to the cheapest JD blades I have found online, get the size of your blades and cross them over to the JD blades and give them a try, I run the high lift blades and these darn things are tanks, most other blades feels like it will take two or three to make the one blade I run on my machine.
GreenMowerBlades.com - Genuine John Deere Lawn Mower Blades for Less!