I'd say that they have a different set of features: use the software that suits best your needs. A default installation of NginX in Ubuntu does many things, whi

I'd say that they have a different set of features: use the software that suits best your needs. A default installation of NginX in Ubuntu does many things, which you need to administer and maintain. Haproxy is simpler because it's not a webserver and does fewer things.