1. How does Nginx compare to Apache?

• For lightly-loaded sites, they are probably comparable speed-wise, but Apache uses far more RAM even under a highly-optimized configuration. For heavily-loaded sites, Apache can easily consume all the RAM in a system causing performance to degrade much sooner than with Nginx. Apache currently has a much larger selection of modules and this can be important in some situations.

2. How does Nginx compare to Lighttpd?

• Speed-wise they are very similar. Both are async rather than process-based. With basic use, both consume a very small amount of RAM compared to many other servers and tend to scale far better than their process-based equivalents. Feature-wise they are very similar. The development model of Lighttpd appears to be more feature-oriented but also more bug-prone than with Nginx, with important bugs going unaddressed for months while new features are added.

3. Is the development branch (0.6.x) safe to use in a production environment?

• In general, yes. Many people use the development branch in production. If you are very concerned about bugs, you might want to wait a couple days after a revision is released to see if any bugs are reported.