IMO anything during those years is fine. 2001-2002 had most complaints of problems. Engines in these have a timing belt that has to be changed every 90-100k miles. So look for lowest possible mileage and if the belt hasn’t been changed expect to incur that expense. It does have an interference engine so if the belt breaks the motor is trashed. If I were you I would look for an 2008-2009 with the 5.7 L engine. They had timing chains. Or 2010 or newer. 

There really is no best model year in terms of reliability since Toyota’s have bulletproof reliability. But in terms of value for the money I think a 2008 would be a good place to go because it’s a lot cheaper than the brand new one which is virtually unchanged from the 2008 version. It has the same 5.7 v8 that goes forever and the same body style as the new one. What I would do though is buy a version with 145,000 miles or less to get the most life out of it. The 2000-2006 are good cars too, but it is a little smaller and lacks some saftey features like stability control.

See below with 2008 being the first model year of the 2nd (and current) generation.

https://www.carcomplaints.com/Toyota/Sequoia/

https://www.motorbiscuit.com/the-worst-toyota-sequoia-model-you-should-never-buy/

https://www.vehiclehistory.com/articles/best-toyota-sequoia-year

http://www.toyotaproblems.com/models/sequoia/

http://www.toyotaproblems.com/models/sequoia/generations/2/