razer keyboards are pretty much the worst range of mechanical keyboards there are.
they have something called a gaming matrix which supposedly increases the response of certain keys, but really what it does is limit every other key on the keyboard at the expense of the 1s in the gaming matrix. they have up to 6 key roll over (10 in gaming). what they dont make clear is UP TO! which means depending on which key combo you hit you could have any where from 3 key roll over up to 10 so its pretty inconsistent.
razers quality is also lacking. yes they get lots of good reviews. but you cant give an honest opinion for the most part because razer will stop sending you there kit if you dont give em a glowing report.
my advice is look elsewhere. you can find better cheaper.
mx browns are a good compromise if you do a lot of typing as well as gaming. but if your more gaming than typing then reds are fine. blues are an office switch. there perfect for typists as the audible click and tactile bump helps tell em when the key has actuated. for games it makes the keyboard noisy.
fps gamers should pick red or black. if your using a bubble key membrane then browns will feel pretty similar but the linear press of the red and black makes for smoother gaming. things like double tap are much easier.
also if your coming from membrane blacks will have a similar pressure requirement. reds on the other hand require a bit less to actuate. its not a huge amount but it is a difference. if your a key masher then blacks are for you. if your light fingered or want to be then reds are for you and there also a little less noisy. due to the fact you dont have to press them as hard so the make less noise when they bottom out.
I actually headed to the store today and then saw the blackwidow and it had a part where I could feel the arrow keys and I really liked the click noises from blue switches. Also, can you explain on how a black or red makes for an easier double tap and for a smoother gaming?
double tapping is easier because you dont feel the bump in the actuator. games like tekken, devil may cry use double tap if you dont use a pad. because the key stroke is smooth it feels more natural as the bump in the middle of blues and browns can be off-putting.
personally i was gonna go for browns but went for reds instead. i just prefered the feel of them. they were less noisy and the linear stroke just felt right.
i can only give you my opinion. if you want blues or browns theres no reason why you shouldn't. they may suite you better than they did me.