I'm about to upgrade my DirecTv service to an HD-DVR, but I'm not sure if I should order the unit from DirecTv or from Best Buy, or Costco. Here is what I've found from all three options: 1. Best Buy is selling the HR22 for $199 2. My local Costco doesn't appear to sell DirecTv units off the shelf (though I'm sure they used to at one point). The only people at Costco who deal with the DirecTv receiver sales were the people at the Cell Phone kiosk, but all they had was a DirecTv catalog and they said they didn't actually have the units in the store. But they were offering the HR23 (I believe) for $189. 3. DirecTv gave me an offer of $99 (which the guy said was $100 off the $199 price). But he said he could not tell me for sure which model # I would get. He said it could possibly be the HR21 (the 320 GB unit) or the HR21 Pro or HR22 (both 500 GB units) depending on what they have in stock. He said that almost everything they have in stock now are 500 GB units...but I guess it's no guarantee. Before I make a decision, I'd like to know what the difference is between the HR21, HR21 Pro, HR22 and HR23. Plus, for those who have ordered an HD-DVR directly from DirecTv recently...what model they send you?