I have 2 or 3 of this model. They have performed flawlessly. I didn't benchmark them because they reside in my backup server, but I can tell you that they run cool and quiet. Samsung has been my favorite brand of consumer drives for the last year or two. Get them, you won't be sorry.
I have a 10 drive RAIDZ2 pool, initially all WDC WD15EADS 1.5TB. I bought two spare as well. The purchase was spread over about 3 months and most of the drives are different manufacture dates. Over the last year, 5 of the WD drives have had issues including one of the cold spares I used to replace a failed drive with. Given this high problem rate, I was reluctant to I replace them with WD drives.
Luckily the SAMSUNG HD154UI 1.5TB is the "exact" same size as the WD 1.5TB and can be used as a direct entire disk replacement. I now have 3 x HD154UI in the 10 disk pool, the oldest being nine months. They are all working working well and have had no failures or
I also now have a 10 drive pool with SAMSUNG HD204UI 2TB drives. It is about 1 month old. No problems so far. I am happy with the Samsung drives!