Is Vertcoin really ASIC resistant?
The primary limiting factor is memory. As N increases, memory starts to become the most expensive component, whether's it's in a GPU or an ASIC. For example, let's say the memory needed to achieve a certain level of parallelization costs $800. Now a GPU chip costs $400, while an ASIC chip costs $100. So the GPU costs $1,200 overall while the ASIC costs $900. This represents only 25% cost savings, making people hesitant to buy a device which is useful for only one task and thus may be worthless in a few years (if GPU mining becomes unprofitable, they could always offload the GPU at half price or more to gamers).


  To me, adaptive-N-factor is just like one of BTC difficulty things. No one is mining BTC with miners whose hashrate is MHs or 10GHs or below, although all BTC miners are using the same proof-of-work algorithm SHA.


Not true. Difficulty is a very simple parameter that does not affect the computations done; it merely is a threshold for determining which hashes are in and which are out. The N-factor actually affects the running of the Scrypt-N algorithm.