For current ElectrumX version:

• ElectrumX is actually pretty lightweight CPU wise. It will run fine with an old Xeon.
• RAM use is 340 MiB not counting buffers. More is always better up to a point.
• Network bandwidth is not bad for a public server, easily serviced with a home ISP connection.
• Total storage is small - 49 GiB total ATM.
• The resource constraint for a public server is really the storage I/O. ElectrumX needs to index each block as it comes in and does some thrashing for a bit each time this happens. SSDs are definitely recommended.

You of course have to have a fully synced and txindexed bitcoin core node already running. And you won't make any $.

The real benefit to running your own server is privacy - you can use Electrum with just your server and node.