I went to Brides and Grooms and had a great experience. I didn't buy from there, because they didn't carry the designer of the dress I bought, but I went there for an initial appointment to try on gowns for the first time and get a feel for what I liked, and they were great. I worked with Carmen.
I've heard really good things about Frank Bernard on Phila Pike in N Wilmington. I've only gone there for bridesmaid dresses, but they get great reviews from me for that. Marba (who works in the BM dept downstairs) is fabulous. I've heard they're great with bridal as well.
Irini's is also on Phila PIke, maybe a mile from Frank Bernard's.
There is also Fantasia and Anastasia's on Concord Pike. I went to Fantasia for a BM dress a few years ago and had a good experience. We went there more recently for a MOG dress and didn't get great service. I've never been to Anastasia's. They used to be in Hockessin I think, and moved to N Wilmington in the last couple of years.
There's also David's Bridal in Prices Corner.
That's all I can think of off the top of my head in the Wilmington area. I'm not familiar with any bridal shops below New Castle County.