MaxUsers

The 50 number is more of a theoretical figure than real.

In practice, once you have 15-20 users connected on the wireless network.....things are going to noticeably slow down. By the time that 30 are on the network, things are going to be really slow. 50 users might be able to connect......but the network would be virtually unusable at that time.....unless you don't mind waiting a minute or two for a new web page to load.

Here, I am assuming that users will be using the Internet, and you have something like a 100 Mbps Internet connection. If your Internet connection is 40-50 Mbps, then things are going to be quite slow with 20 users.

If you have a 100 Mbps Internet connection.....and....you really want to have 50 users on the network....then you will need at least two AirPort Expresses. If you wanted to have 70 users on the network, you would likely need to have a 150-200 Mbps Internet connection and 3-4 AirPorts.