Heretic777: I just looked over the Impulse Xmas sales list and its just terrible. Most of the discounts are only 50% off. They will have to do much better if they want to compete with Steam and GG.
Kabuto: Your killing me with this only 50% off is terrible nonsense.
It depends, let's take Arkham City, 50% off isn't that great of a deal... because it's been 50% off everywhere already about 3 times in the last month. It's base price hasn't gone down, therefor it's had the exact same sale price. Anyone willing to pull the trigger at the price probably already did.
Now, 50% by itself isn't a bad or a good discount. But when you check the sale price some games at "50% off" aren't all that great of a deal. They've been out a few months and their normal price will meet or beat that price in a couple more.
50% off a 5 or 10 USD game that likely won't be going a lot cheaper even in the next year or two, is a good deal, generally. But you have to consider whether you'll be able to pick it up as part of an indie bundle or other pack for a lot less. So again, neither good nor bad, depends on the buyer, the game, and what the base price is.