Many many developers all over the net respect NASM for what it is: a widespread (thus netwide), portable (thus netwide!), very flexible and mature assembler tool with support for many output formats (thus netwide!!).
Now we have good news for you: NASM is licensed under the "simplified" (2-clause) BSD license. This means its development is open to even wider society of programmers wishing to improve their lovely assembler.
Visit our nasm.us website for more details.
With best regards, the NASM crew.