For a non-frequent AA flier, we have a very organized forum here, which has a wealth of basic information in the FAQ (where it says "Please check here first"). There should be lots of info on the NGBC seats there and in the thread linked by 3Cforme.

The 763 is AA's internationally configured 767, with angled lie flat NGBC seats in business (sold as first, domestically). It's much more comfortable than a standard recliner.

AA does have plans to upgrade the hard product on the 763, but we likely won't see that in play until 2015.

I'm not familiar with other carriers on this route, but on AA, the DFW route is definitely preferred to the LAX route, which is on a 752.