The Black Widow's use Cherry MX Blues, but they're modified to have a different actuation force and travel length when compared to "real" MX Blues (a la CM Rapid/Stealth/TKL/XT, Filco's Ducky's, WASD v1 and v2, etc).
If looking for a mechanical keyboard on a budget, I HIGHLY recommend the Cooler Master Quick Fire Rapid, the Quick Fire XT, or the Quick Fire Stealth (I prefer them in the opposite order I posted, but with Green or Brown switches).
The Rosewill RK9000/RK9100 CAN be excellent keyboards, but some are made by Costar (good!) and others by a "newcomer" to the mech-board game (not good!).
*Das Keyboards is having the same issue, huge decline in quality since they switched OEM
The next step up puts you at around $120-150 and, quite frankly, Ducky rules the roost (get it?) here. The Zero, Shine, Shine II, Shine III, and all the special editions means that there is literally something for everyone! I love them, they have an insanely high build quality, and it will quite likely be the last keyboard you ever need buy.
Filco are popular, as are Matias, and use the Topre RealForce switches; a different type of mechanical switch from the Cherry MX. They are nice, but which you prefer is up to you.
Hope that helps!