We are using ResourceMate 3.0 Plus for cataloging, circulation, overdues (via email), reports of all kinds and as an online catalog. We,too, have around 4000 items which are barcoded and circulation with a scanner is so easy. We do not use barcodes for patrons because we have found that people tend to forget their cards. We know most of them and can quickly key in the first few letters of their name which brings their record right to the screen.
I can't imagine any function that a church library would need that is not available in RM. The initial purchase price is reasonable and the annual cost is just the annual fee for support (which includes upgrades) and the occasional purchase of barcodes and labels.
One of my favorite features is that RM allows you to do volunteer entry of new items at home and then upload the data to your church computer. This enables me to catalog at home, often at night, when I would not be able to work at church.
I wish you well as you make this important decision.