I downloaded GF 1.5 RC4 and noticed a few oddities.
1) The Admin label isn't working for checkbox form fields. (It did work for a phone number field, and those were the only 2 types I tested.) For a checkbox field, the entry in the Admin label is ignored and the first checkbox value is used. Clarification: the Admin label is not shown on column view, but it is shown when viewing an individual form submission. When you edit the columns to appear in the Admin panel, the field name is not shown for a checkbox field. Instead, each of the checkbox values is shown.
2) When attempting to re-arrange the columns in the Admin panel, the Edit window comes up and the functionality works, but it takes a portion of the background image from the site. What I see is the top part white, and the bottom portion the site background, which makes it difficult to use. The site is running W3 Total Cache and this problem goes away when that is deactivated, but I was under the impression that plugin didn't cache admin pages.
3) I also set up the PayPal add-on. On the mapping of the PayPal fields to the Form fields, the width of the drop down extends well outside the viewport. I think that is because I have some long text in checkbox values, so that when you populate the list, you accommodate the longest value. I think it would be better if you shortened that and added an ellipsis if it were longer than some value. I didn't even realize there were drop downs until I finished my morning coffee :)
The forms for this are on draft pages, so if you wanted to see this live I'd have to email you login credentials. Just let me know if you want them.
Hope this helps.