The discussion regarding buy vs build for software is as old as software itself. Is it possible to find one answer? No, of course not, but having said that, lately I think that a push towards "buy" is quite common. Of course this is very good in some situations, but quite often I think "build" is to be preferred.

You probably don't want to be standard when it comes to the domain specific parts where you have your competitive edge. It's as simple as that. Another factor is that the business of software development has become much more efficient at building domain specific application (because of domain-focus, agile practices, experience, craftmanship...), while at the same time the standard packages have grown too colossal, often being harder to configure than to build what is needed. It's also the case that typically the standard package won't do exactly as you want, no matter how much you configure.

The time to market with good quality is much better today than before when it comes to "build". Dare to take the build decision!