As usual, I have to recommend www.adastrafanfic.com. There is writing of all different ratings and pairings there, and the writing quality tends to be quite high.
I had checked out the site before and didn't find it especially useful, but I checked it again on your advice and there are certainly a few stories that I will read shortly. Not sure why I passed over the site on the last go around, I may just not have navigated it properly. Thanks.