My local bestbuy has a huge selection of keyboards. I Was getting a new mouse and tried em all out. Corsair K70 mx blue is the keyboard in comparison.
- Razers new switch felt pretty much identical to the mx blue keyboard that was sitting right next to it. I really couldn't feel much a difference at all. You can get refurb'd ones for pretty cheap
- The posiedon Z thing... It was definitely better than a membrane, but something about it just didnt feel "quality" when I was jamming on the keys. Its backlit though, which is a major plus for it. It was similar to an mx blue, just a bit more 'squishy'.
- Used mech's are great value if they are in great shape. Amazon has a huge selection. I would be very comfortable buying that razer, it felt pretty good to me.
Finally, built a computer for a friend of mine this week actually, and he cheaped out and got a cooler master devastator keyboard/mouse combo. The mouse was crap for me (completely flat!) but that keyboard was probably the best membrane keyboard I've ever seen. I personally own steel series apex keyboard (htpc keyboard), and its very nice, but the devastator definitely felt much better.