I'll add my 2 cents too on that... from the perspective of someone who's been using computers since 1984 and whose 20MB (yes, MB, not GB) Hard Drive from 1987 is still working.
Technically there is no difference whatsoever between an Internal Hard Drive and an External One. The greatest majority of drives are the same: one without a casing to go inside the computer, one with the casing that adds input/Output ports (Firewire, USB, E-SATA, Ethernet) therefore the mechanical life, out of the factory, of an external vs. internal drive is pretty much identical. What makes the external more prone to damage and death is the fact that, being external, people are more likely to move it around, bump it, etc. Since I pay so much attention to what I do with my external drives, I have had 2 internal drives die, but no external (so far, knock on wood). Reviews need to be taken with a (large) grain of salt as for their very nature are subjective.
The advantage of the drive you chose, Ivan, is that you can remove it and replace it with another drive without paying the extra $20/$30 of the casing (you only pay that once). I'm not sure this is the cleanest solution as it only allows you to use one drive at a time. There are casings out there to transform an internal into an external for around $30 (I find this most useful for laptop drives). The real advantage of internal drives are: speed (SATA is a lot faster than the other buses) and the possibility to mount them as RAID (2 of my internal Hard Drive drives are configured as RAID0, which makes the computer see them as if they were one, but obviously at much higher speed since now there are 2 heads writing and reading at the same time).
This concludes today's Hard Drives 101.