To start, this show is by far my favorite show ever! However, this review isn't about how great it is. This is for my fellow fans wondering about the quality of this purchase. I bought this because it's cheaper than buying each season separately (I own a SD physical copy of this show, too).
First, I was wondering how the HD compared to the SD. Honestly I think the HD is only slightly clearer in picture than the SD version, but not enough to really impress me. So, it's not a waste of money if you buy the SD version. It'll save you $10.
Second, AND THIS IS MY BIGGEST COMPLAINT, the episodes can get a bit glitchy (could just be my internet connection), BUT the last episode of Book 1: Water has 2 full minutes cut off from the episode. The description says it's 26 minutes long, but I counted the minutes and it only went to 24. Not to mention, parts of scenes were included in the cut off. This disappointes me greatly. I made sure my internet connection was strong and I even restarted iTunes. I know it's a glitch in the purchase. If this gets read by Apple maintence or whoever can help, I would appreciate some trouble shooting solutions; otherwise, be forewarned that this may happen to you if you make this purchase. **To be clear, this is from Book 1 alone. I still have yet to watch the other two series for any glitches.