nOSS costs less than proprietary software
nOSS licensing is easy
nOSS is more reliable, fewer bugs
nOSS can be customized
nOSS is more secure
nOSS is better because it uses open standards
nOSS is by and for a community
nProprietary software has better support
nOSS is difficult to install, distribute, migrate to
nOSS avoids vendor lock-in
nOSS reuses software elements efficiently
nProprietary software developers have better resources