We have been using SSHDs for 6 or 7 years and SSDs for a little longer. All SSHDs are still in use, we have not had a single failure with about 10 here (and 2-3 times that in user builds) and they ranging in age from 2.5 to 7 years, Three of the early SSDs we bought failed.
One after about 2 years, it's warranty replacement 3.5 years later. In a 2nd box, the SSD died after 4.5 years. Both of these had their lives extended for 6-12 months after reformatting in an external drive and doing the diskpart thing. Those failures were high end early generation models when 120 GB was as bout as much as could be set aside for an SSD. We have had no failures with later generation designs (250 -256 GB) later generation models. As long as you stay away from the lower end or older generation stuff, you should have no problems with getting 5 years out of either.
Presently, our base configuration includes a 250 GB SSHD and a 2 TB SSHD If asked to build a gaming box, and budget doesn't allow both, we recommend the SSHD now ... with an upgrade to add the SSD for OS and programs when budget allows. If building a gaming box, with OS and programs on the SSD and your game library on a HD, the games get squat from having the SD.
-Gaming Performance improvement that you gain from SSD when game library on HD = 0%
-Gaming Performance improvement that you gain from SSHD when Everything on SSHD = 53.5% speed improvement
http://www.tomshardware.com/charts/hdd-charts-2013/-17-PCMark-7-Gaming,2915.html
Seagate SSHD - 9.73 MB/sec
WD Black = 6.34
973 / 6.34 = SSHD speed is 153.5% oh the High perfomance HD
Both typically come with a 5 year warranty, As or boot time performance ....
Windows boot time on same box
Samsung Pro 256 GB = 15.6 secs
Seagate 32 TB SSHD = 16.5 seconds
BTW, 1 post per topic please