Domestic first is still special to me, though less so now with recent cutbacks. Best aspects are the additional width (no rubbing elbows with my seatmate), less competition for overhead bin space, and better service from the FA's (but don't treat them as your personal servant). The first time I flew first (AA DFW-LAX in 2009) it was so exciting, one of my best flights ever. Of course, I'm speaking from a mostly coach flyer's perspective.
Enjoy your flight.