I've been on the O/R Mapper bandwagon for a while and just came across NJDX from Software Tree. I think that Deklarit and LLBLGenPro are two of the finest on the market, but I have to admit that I've also taken a liking to NJDX quite a bit. Both Deklarit and LLBLGenPro have a lot to love about them, features which are fundamentally different from each other, so what does NJDX bring to the table? Simplicity. i've seen a few iterations of the product and it appears that they tried mainly to make an O/R Mapper with no learning curve. To a large extent, that's exactly what they've done.
I downloaded it and installed it. There are some great tutorials which walk you through using it. About 20 minutes later, I created a project and tested it. Viola. I'm still a little perplexed about what's going on b/c I've ripped apart the files and I can't really tell where the code is being generated. But I took a quick query and populated a datareader with it, iterated through the reader and filled a Listbox control and it takes one line of code to do. compared with the roughly 15 lines of code it normally would have, it's pretty impressive. I tried the usual tasks, changing DB Column names, absolutely simple. I tried mapping the fields to a different column, no problem there either. All in all It's pretty darned impressive and easy to use. If you're looking for an O/R tool, it's defintely one worth taking a serious look at.