All years are good! My brother severely abused (heavy towing and lead foot) his 2008 Sequoia Limited (first year of 2nd gen) to 300K miles, and still sold it for $12K last fall.
Some earlier years had some unique problems that were fixed in 2010 I believe.
Because I'm a purist, i'd personally avoid the rear air suspension and go for an SR5 or Limited model for simplicity...YMMV
A 2018 with low miles is golden, just check for maintenance records and severe rust underneath. The 2018 also has the face-lift and better looking headlamps etc...
I have a 2012, no issues, love it.