Based on empirical and anecdotal evidence, along with a long exposure to directv products I've come to the conclusion that the newer stuff is a lot trickier to install and the tolerance levels much narrower. In the old 2lnb round dish days, you could line up a dish with very little trouble and for the most part the receivers were all pretty solid and held a signal just fine.
The 5 sat setups are obviously a lot harder to align and the dish is much larger and heavier and harder to keep solidly in place.
I also think the receivers vary greatly in their tuner quality, tolerance ranges and software influence. I've seen people have the dish dorked about endlessly and then their signal problems go away when they change from one receiver to another, even where the two receivers are the same model.
I've also had signal issues and reboots related to signal issues that I was told was absolutely, positively an issue with the dish or cabling, only to have those problems dry up when a new software release came out.
Directv fanboys often note that the latest incarnation of directv's product offering is much more complex than the older products. That may be the case, yet its the technology that directv chose and rushed out to market.
All that having been said, if you have proper dish alignment, well made cables, and receivers that are working properly and within the proper range of tolerance, it does appear to work fine 99% of the time.
To be fully fair, my one brief experience with Dish network was that the equipment ran too hot and gave me trouble, they also had signal issues, and they gave me the worst customer service experience in my life.
Just to round it out, I get far more outages and signal problems with cable than I've had with either satellite provider.