I also endured the dreaded "Unfortunately com.sec.imsservice has stopped" error message every few seconds. My issue wound up being a program called "Thinkfree Document Viewer". Uninstalling it stopped the error message immediately and now the phone is "right as rain" after the Lollipop upgrade.
Thinkfree Document Viewer installed with some MobileIron apps my company rolled out a number of months ago. I wound up uninstalling MobileIron a couple months back, but Thinkfree Document Viewer never uninstalled. It also likely never received any more updates to make it compatible with Lollipop.
In my case it was neither a Lollipop, nor Verizon issue. But a downloaded app that was apparently non Lollipop compliant.
Hope this helps someone.
So I have the com.sec.imsservice issue, as well. How did you narrow it down to that specific app? Thanks