I'm surprised at the www supporters. Do not do this. Down the road, you will want to use subdomains (app.example.com, dashboard.example.com) and choosing www out of the gate will make it more complicated then it's worth. If HTTPS is required, then a certificate with www will always get in the way, get a non-www and add a subject alternative name, or get a wildcard.

It is much, much easier to redirect all non-www traffic to www if a subdomain is not specified then otherwise and a wildcard or SAN-enabled certificate will make it much more flexible in the future.