3 Answers

They are both on sale at The Home Depot today (late October, 2015).  The 3570 is about $100 more, but does have a larger capacity, so you could do fewer loads and enjoy some energy savings.  Other than that, they seem to be identical.

My new roommate had to sell his LG w&d, got good money for them, too. They were great. As if in consolation we bought an LG refrigerator. I'd follow Phyllis' advice and get the larger capacity. More economical as you'll have fewer loads to wash in the long run.....

By shortening the contact surface of the waiting pallet and adding the indirect impulse surface, the impulse-generating escape wheel starts link moving before it's finally released. This significantly shortens the distance that the escape wheel link must travel before reaching the impulse pallet. In a traditional construction the escape wheel first has to overcome the recoil and then link hurry after the impulse-taking pallet.