I had an Accord, and wanted more cargo versatility. Drove several other small SUVs (Rogue, CX-7, EX-35), and the RDX was the obvious choice. The EX-35 was great, but just not enough room. The others were not comfortable enough, both in seat comfort and ride quality. The RDX does seem too stiff on city streets (my '98 Accord was smoother). But it has a solid feel, very smooth on the freeway, great acceleration, plenty of upscale features - basically a blast to drive. My wife can have her cushy Lexus. I prefer the sporty Acura.
Technology package, comfort, quality.
Remote rear hatch release, auto wipers and headlights, a little more forgiving suspension.