Dan, the reliability you've experienced with your Tahoe isn't out of the norm. It also isn't out of the norm for them to require repairs.
General repairs for GM trucks do not include transmissions. It's usually the fuel pump and/or sender, hub bearings, gauge clusters and blower motor resistors.
Once in a while, people are now having to have LS engines replaced because of sludge build-up in the heads and oil pan. That stems from improper maintenance, but it's a nasty result of less-than-neglectful practices. It doesn't take much outside of 4K service intervals to build up that sludge. Synthetic blends at the very least are a good way to stave that off.
Pretty sure if I ever buy another car, it will be a GM. I know what's going on with them, how to work on them and familiarity goes a long way for me.