Yes, the second Gen Tahoe’s (2000-2006) and its re-badged counterpart (GMC Yukon) were reliable.  See @ 5:43 in video below:

https://m.youtube.com/watch?v=aUe0x9s9nyE

Those years were decent and the tahoe/yukon had the same reliability essentially because they are rebadged but its getting old

Those years were solid. The Yukon is just a rebadged Tahoe. They share drivetrains so reliability would be equal among those and the Suburbans.

We have a 2002 Yukon XL Denali with 194,000 miles. The transmission went bad at 152,000 miles and we got a rebuilt one. We have had what I consider normal repairs done for a car we have had for 20 years.We had a 2003 Avalanche which was unfortunately totaled in an accident at 155,000 miles. I think it was going to be needing a transmission rebuild soon anyway which I would have done as that was a great truck. It was kept outside in Virginia and had NO rust on it what-so-ever. I think shortly after these model years, GM quality took a nose dive.

Scotty actually has a video of an early/mid 2000s. Get on YouTube and watch that to learn more. My opinion is they actually were built pretty well. My uncles 2004 burb is pushing 300k and still is his daily driver. He’s had to swap transmission out at like 200k but the motor is sound. 

Those years were pretty decent. After the 2008 shake-up GM started cutting costs. Keep in mind it's 20 years old and things just generally break down with age.

The engines in these vehicles from 2002-2007 were either the LQ4 or the LQ9 (for V8s) and were really good engines.