There are several in depth comparisons on YouTube.
Two main standing out differences are much bigger cargo capacity and significantly more powerful engine - at same displacement. The rest is gadgetry and personal preferences.

 

Alex on Autos has be pretty harsh on lexus lately. I have called him out on it on his ES review.

 

Former Acura owner here who did not have a good experience. I was a big fan of Honda and Acura. Had an Integra and a 2005 Acura TSX (solid, good engine, made in Japan, well made) that had no problems.

Then had a 2010 Acura TL and it was a nightmare. Around 30k it needed a complete transmission rebuild due to 3rd gear pop out and grinding. Then the engine started to suffer from heavy oil consumption. Had to battle the dealership and corp for about 12-15months; corp/dealership giving me hard time about oil changes, etc. Ticked me off to no end. A few days just prior to end of powertrain warranty, engine was making a funny ticking sound. Took it one last time, engine had NO oil, and dealership finally admit the car needed service. Result was a new engine. After that experience I got rid of the TL for the LX570.

Be very careful of the new Acura's and Honda's. They are NOT the same as the ones that were built in Japan, and their reliability has been declining for the past few years. I read an internet article some time ago that even one of Acura's executives admit the decline in reliability is a concern that needs to be addressed.

The new RDX SEEMS nice, but I'd wait a few years and see how the engine and transmission holds up. Until then, I suggest sticking with Toyota or Lexus.