With each upgrade I lose my custom toolbars and have to recreate them. Upgrading from 3.7 to 3.8 Beta had the same issue. For example in 3.7 I have a main window toolbar called "Dave Toolbar" and an editor toolbar called "Dave Editor Toolbar" each with just the commands I use often:
After the upgrade to 3.8, it prompted me to bring in my settings from 3.7 (which I said yes to) and I got all my Options, but not my toolbars. So I have to rebuild them again. This is not a critical issue, but it would sure make upgrading easier!