This app is good in theory... It was easy to install, and the styling was nice. It has three major flaws, however, that led me to uninstall it:
1) It applies price breaks when quantities go up... but it keeps those price breaks when quantities go down. So, a user could add 5 items to the cart, get the price break, and then from the cart page reduce the quantity to 1 and still get the discount.
2) If you have a product with multiple variants expect lots of setup. You have to set a price break for EVERY variant, and some of my products have 40 or more. There is no way to "bulk" add the same discount tiers for every variant of a product.
3) It is really laggy. It takes a while to load the price breaks onto the product page, and the cart page takes a while to update. I could see lots of customer confusion.