Original sentence: However, ReactOS developers argue that a Unix-style OS is not the only or necessarily the best type of OS, that the design of NT contains many ideas which are an improvement on the Unix way of doing things, and that an OS which is more like Windows at a lower level is more likely to be able to easily run Windows applications
Edited sentence: However, ReactOS developers argue that a Unix-style OS is not the only or necessarily the best type of OS, that the design of NT contains many ideas which are an improvement on the Unix way of doing things (even though, many would argue, Microsoft has not made the best use of that foundation), and that an OS which is more like Windows at a lower level is more likely to be able to easily run Windows applications