It only took 3 weeks for a GPU miner to be released for MMC that has a hashing rate an order of magnitude greater than what is possible with CPU mining. Compare to Primecoin (and Datacoin et al) where after 1/2 year and much greater economic incentives, attempts at producing a GPU miner haven't amounted to much of anything (someone released one, but it was not faster than CPU mining; nobody uses it).
It's counter-intuitive, but a GPU miner is very good news for MemoryCoin. It removes the unknowns. We have a pretty good idea now of what GPUs are capable of compared to CPUs and it's not a deal breaker. With PrimeCoin and other coins claiming to be GPU resistant, usually through complexity, you don't know if
a) the dev has been GPU mining all along
b) private GPU software have been competing alongside
c) whether a GPU miner will be developed at a later date when there is sufficient economic incentive.
We have an algorithm that's simple, that relies on limitations of the hardware, that's been tested and has good potential for long-term GPU/ASIC resistance.
I think what'll you see happen over the next few weeks is that GPUs will drive the difficulty up so that they find profits reduced and so will switch back to other coins.