I just got off of the phone with Lotus Support. I have some good news and some bad news.
Good news - one of the new enhancements with Smart Upgrade in 7.0 is the ability to Upgrade Multi-User Installs. This is great to hear as we have a fair number of multi-user clients.
Bad news - with the 7.0 Client Installer, a Registry key is not being set prior to the actual installation. The install is successful, but upon starting the Client you are prompted with the new client setup wizard asking for User Name, Server Name, location of ID file, etc... This has, in my experience, only affected Multi-User installs and Single-User installs will upgrade and start successfully.
My PMR is being escalated to Development to get this corrected. I can hope that there may be an update to the installer or possibly a 7.0HF1 Client. While there wasn't a ton of focus on the UI of 7.0 being updated, it could possibly keep people from upgrading clients depending on the number of Multi-User installs. I will keep you posted!