Well Notes is god-awful. I've never been forced to be a user, but I've had to do support for it and if you've been exposed to absolutely any other E-mail system in the last 15 years it's pretty easy to understand. I know there are organizations that keep it because of the fantastic ability to manage and associate documents within Notes, but that's something Microsoft largely addresses with Sharepoint, which you'll probably also be getting. And plenty of organizations never touch the document sharing aspect at all, or it's kept in place just because one subgroup of users want it.
I hate Outlook from a support perspective (Outlook keeps user settings too many different places and is extremely heavyweight for what it does), but it DOES work and it integrates very well in an all Microsoft environment. You probably won't ever see or deal with any of that unless someone expects you to manage your own Email on a local client, something I highly doubt you'd be dealing with in 2013. For you it's just going to mean a completely different GUI that, as a literate human being, you'll accept and adjust to.
Speaking of, does GM still have the big association with EDS, or is this all coming from in-house IT? Most Lotus users tend to be associated with IBM clients, which means banks and large government entities. I'm a little surprised that you're still using it.
