I have bought two of these drives in August 2011; couldn't resist when the price was only £64! One of them has been on 24/7 ever since and the other one is for backup. As usual, I have formatted them and started using them without any problems. I now have 8 Buffalo drives, ranging from 250GB to 2.00TB and they are all still 'alive'. I think the oldest one is about 6 years old.
The only negative thing about these particular drives is that now and then they can get a bit noisy; in fact, they are the noisiest of the whole lot - not sure why, maybe the design? The noise comes and goes and it is not a problem, more a curiosity, as the older drives are so quiet.
I know some people have had problems with their Buffalo drives; either I have been lucky with my 8 or it may indicate that the brand is actually pretty reliable on the whole. I had considered other makes every time I needed a new drive but in the end I had bought another Buffalo because it is what I know.