GF has a 09 Denali and I love driving it. 2nd row buckets make access to 3rd row much easier. Also, I think i saw where you said you would put the baby seat in the 3rd row, everything I have read is that baby stays in middle row and close to mom. Also much easier for kids to access third row than adults.
Her rig has like 45K miles, no real issues. Couple little things (fan motor, rear defrost wiring). My sister in law has an 08 with around 120K and has not had any issues.
GF and I test drove a new Lexus ct200h yesterday. She drives a ton of miles and the 40mph would sure be nice compared to the 14 she gets in her Denali. Will probably sell my tundra and get the Lexus, and then I get the Denali.