Summary: I have bought this keyboard just over a year ago to replace Gigabyte's Osmium keyboard which had shutdown issues. This Roccat performs very well. Nice reaction. Nice feel. I haven't come across any combination issues. I haven't even programmed it yet. Well, don't feel I need to. But one thing really surprised me. The black plastic coating (or is it paint?) is coming off the most frequently used keys, WSAD.
Summary: This keyboard has some major rollover issues, for example in BF4 whilst holding certain combinations of WASD, pressing M to check the map does nothing unless you stop moving. Games like Hero Siege that make heavy use of WASD and the arrow keys are also a problem for this keyboard. I even went ahead and got a replacement hoping it was an isolated issue, but was disappointed to find it exhibited the same issues.