Spend more get more, spend less get less. Theres always a rule to the exception. I personily have never heard of a Raptor failure. Yes there pricey but they just last wether in a hot or cool cases. It seems that if you don't have fans on a Seagate there going to die sooner or later as I've read here. Of corse look at how much your paying for them, there very low priced. I'm not bashing Seagate, but I can only go with the "facts".
Just wait, and you'll see Raptor failures. They've not been out long enough to see a lot of failures from them.
All the drives (not a lot, but maybe 10 or so) I've had in the past 10 years at home have been Seagate, and I have no failures yet. So, your facts seem to be slanted in one direction. If you were to take all of the data from all Seagate products across the globe, (and from other manufacturers as well), I'm sure you will see something different.
I think you should look at particular models of Seagate and compare. Each model has a list of operating specifications, and they can vary widely. So you cannot make a blanket statement about one manufacturer based solely on your perception of one model.
Maybe you should also throw a Raptor into a non-ventilated case to see how long that lasts as well. Most folks who are buying Raptors have the nicer cases where they are building them for performance, which usually means more air flow and cooler temps. That could, in effect, lower their failure rate. Actually, take any drive and don't give it much circulation. I bet a Raptor would die sooner or later without circulation too.
We have around 250-300 disk drives (FC, SCSI, and SATA) in our server rooms, with half of those being > 5 years old and I've had 2 failures in the past 3 years. And guess what, they are all Seagate.