Defending the BW:
Build quality isn't bad; in fact I would say it's pretty good. You can look at the reviews that some of the other GH'ers posted for the BW (
like this one), and even they said it's not poorly built. It's by
far the best built keyboard I've ever owned, but this is my first mechanical. The body does not flex or creak as bad as my others (namely the MS Natural 4000, the "best" rubber-dome I've had). And you still get the same Cherry Blue switches as you do in the Rosewill - quality in the key switches, where it counts the most. Additionally, both keyboards come with a braided cable and gold-plated connector.
Also, I haven't been able to pull any of the keys off my BW with my bare hands. How that's even possible, with the smoothness of the keycaps' sides, I don't know. Hyperbole, perhaps? Maybe I have a weak grip compared to others. I had to use some tools to pluck the key caps off.
Finally, the keyboard was much cheaper than the Rosewill was. It also has media keys and macro keys, if you're looking for that.
And now the drawbacks of the BlackWidow:
The switch feel is different from row to row. So, the QWERTY row of keys doesn't feel the same as the ASDF, which feels different from the ZXCV row of keys. In fact, number row and numpad also feel different. I don't know why that is, and I don't know if this is apparent in other keyboards such as the RK-9K, but this is something I have to mention. The difference in feel is subtle though, but if you're picky like most of the people are on GH, you will probably notice it.
Additionally, my left shift key was mushy, so I swapped the stabilizer with one from the + key on the numpad. Feels like the other keys now. Take that however you will.
And of course, the stuff already mentioned: lack of NKRO and the glossy finish. FWIW, the glossy finish, unless you're a stickler for cleanliness, isn't a problem for me - I've wiped it down only once so far. Lack of NKRO hasn't reared it's ugly head too often for me.
Last points:
Do I have any doubts about its durability? No. This keyboard will probably last me a
very long time, unless I did something deliberate to it.
Would I buy the Razer again? Yes, mushy shift key and all. I can't justify paying $30 extra for NKRO and lack of media keys. It's a solid board.
Do I enjoy typing on this keyboard? You bet.