Windows vs UNIX is like RISC vs CISC on cpus: each one has its flaws and advantages. The unix api philosophy is to keep the functions as simple as possible, and achieve the same tasks through serquences of configuration calls, rather than big monolithic APIs that have the settings all specified explicitly.
I'm not going to argue which one is best, as my personal preference falls in between, if only slightly closer to the Windows way. The Windows API is often overengineered, while the unix way feels overly simplistic.
In fact, the comparison between Windows and unix here is pointless: this project is reimplementing Windows, not unix. Anyone who truly thinks ReactOS won't be used becuase they already have Linux, probably wouldn't care about the project and so wouldn't be writing to our mailing list. I believe Riccardo referred to people developing apps for ReactOS/NT5, when they can write them for NT6 instead.