Express vs. Standard -- what's missing?

I'm trying to make a decision on which edition to install—Express or Standard. Specifically I'm hoping to learn in painful detail exactly what I'd be giving up in terms of reporting with Express.

The most I've been able to come up with after much searching is "Some advanced analytics are not supported," or "If these services are not configured, you can access only current status reports."

Thanks, but that just doesn't do it for me. I've never used TFS nor Agile methodologies, so I'm flying a bit blind here. Exactly what kinds of reports will I be missing?

Same goes with SharePoint. What features does the integration provide that I'd miss out on?

Also... what's involved in upgrading later, should I decide to go with Express for the time being? I'm to understand that the setup package installs SQL Express on the same machine (Server 2012 R2 in my case), but if I upgrade I'm not going to want a resource-heavy SQL Standard instance on that same VM. During the upgrade will I be able to migrate the data to a different VM (one that I've provisioned for dedicated SQL Standard hosting)?