Don't you mean the price of buying it is too expensive?

It's not about the sequential read/write performance, which is only about 3x or 4x the best that HDDs can offer. It is the access times, which is about 0.1ms and extremely fast compared to HDD's +10ms times; about 100x difference. For operations that involves tons of random reads and writes, like when on boot, SSDs are very responsive. If it takes you long minutes to boot up or do a virus scan that you would like to reduce by a lot, SSDs can do it.
It is more of a QC issue. Theoretically, the NAND storage is good for at least ten years. Most of the failures at this time, isn't related to the actual NAND storage. Most of it is probably due to firmware, manufacturing defects or poor QC.

Guys...is WD caviar red any good---durability and performance wise?

Which one is reliable for 3TB HDD? Seagate or WD?
Need it just for storage/backup.

Of course is black series and it runs hot around 2 Celsius more than blue

Well my blue and black haven't break down. What I like black is due to 5 years warranty. 

My WD Blue and Black have been running everyday for 3 years now, still in perfect condition (no weak sectors or anything like that).

The temperature difference between them is not important, it is too small to make any difference. What's important is the cooling of the hard drive. With proper cooling you should be able to maintain all drives below 45C

In the past, my HDD all dies after 1-2 years due to improper cooling 

What's the best bang for buck 2TB harddisk in the market now?

I'm planning to use it for HTPC so performance isn't the exact priority.

Which size has the best price to capacity ratio now? My last harddisk purchase was a 2TB Samsung HD204UI about two years ago. It is still running good and it runs at temperature much lower than WD.

IINM in March, I shocked when my PC run HDDcheck during bootup, like deleting files and recover files.
Feeling it must be something to do with my HDD, i went on to run HD Tune and get the following results of my C Drive :

https://forum.lowyat.net/index.php?act=Atta...post&id=3414761
Initial it got 12 current pending sectors, upon googling i realize it is another meaning of bad sectors, so i do backup ASAP.
After 3 weeks, my PC hang when surfing internet, knowing that the HDD had reach its date, i force shutdown my PC and restart......I cannot see anything on my monitor, not even BIOS Splash screen!
https://forum.lowyat.net/index.php?showtopic=2784581&hl=

One good thing of WD Black is we may have ample time to do backup before it finally gave up