Personally, I was turned off with Razer because of reports of bad QC, bad quality, and bad customer service. I would not buy a K90, as I discovered that the keys are not laser etched (though it is advertised that it has it in some places, it is incorrect), there are no functions listed on the number keys, and it has an issue with "sticky" keys (random keys get pressed for no reason; a firmware issue) that Corsair refuses to fix.
I would suggest reading up on mechanical keys before buying a keyboard: http://www.overclock.net/t/491752/mechanical-keyboard-guide#post_6009482.
I had it narrowed down to either a K90 or a CM Storm Quickfire Pro (it does not have programmable keys), and went with the CM with Cherry Red keys. I think they are perfect for typing (added 10 wpm for me), though some people don't. Cherry browns are a nice compromise between gaming/typing I hear.
It is a durable setup: Cherry keys are rated for 50 million actuations, it has a steel backplate, and a 2 year warranty. It is a fantastic keyboard and I couldn't be more pleased with it. I'd highly recommend it.
If you have to have programmable keys, I would check out Cooler Master, CM storm, and Gigabyte, as I recall they each have a model with programmable keys.