I generally go for the physical disc, and if it has an HD download attached with it, so much the better.
For my sob story, I purchase season passes for the Star Wars: Rebels cartoons since I watch that with the family regularly. Season 1 was as expected, so I purchased Season 2 early on. However, recently Disney decided to split Season 2 into two parts. Some of that is understandable, with Season 1 having 13 episodes and Season 2 now being projected to have ~20 episodes. At the same time, there was no mention of the split until January of this year, which ticked a lot of fans off. Given that the more recent episodes suck anyway, I'm not in a big rush to purchase the second half of the season.