Installing Flash Media Server is like a 2 minute job. It runs better on RH enterprise or Windows platforms.

As far as it being worth it, it depends on your expertise with flash. It can take some time getting things going the way it should, licenses are expensive, operating systems re expensive and there is a learning curve. It also depends on if you are doing progressive vs streaming movies. Do a lot of research, there are tons of places on the web to give you code for actionscript, but Adobe is lacking with their free support docs.

There are alternatives to FMS as well wowza has one and red5 which is an opensource java oriented streaming server is another. Red5 is not very mature yet though.