Hi there!
I know it is so hard to trust leaving your lo with people you don't know. When we joined our church we were so pleased to here that all of the nursery teachers have background checks

We could go in and spend the entire service with them if we wanted to (at any time). The first several times I took my dd, I sat in there with all the caretakers. It was really reassuring to see what went on and to feel totally welcome to barge in whenever I wanted. We also have a cry room and there are times that I don't feel like leaving my youngest in nursery. It is a perfect spot to go and nurse and still be able to hear the sermon.
Wanted to add....our church nursery system is FABULOUS! They have this system (similar to Melissa's church) where the kids get a sticker on their back and the parents get a number. If there is any issue what-so-ever, the nursery has the childs number put up on the screens so the parents can go get the kiddos. The parents also have to turn their sticker in and initial the sign-in sheet to get their babies back. It is a wonderful system!
I hope you find something that you feel comfortable with. I know that I SOOOO look forward to Sundays. Not only b/c it is our time of worship but also b/c it is an hour and a half of baby-free time

We don't have babysitters so this is literally one of the only child free moments of our week!
Good luck finding something you are really comfortable with!

Shelby