My advice is to become well versed in common problems for every generation of the vehicles you are looking at. No brand is immune from issues, every vehicle has a weak point and every vehicle has potential issues you'll probably deal with at some point. The key is to weigh those problems and determine your risk tolerance for each issue. Yes, maintenance is important, but some vehicles are just inherently more or less reliable than others due to certain pattern failures you can weigh out.
Those pre-2007.5 chev's (known as the Silverado Classic, or "Cat-Eye Chev") have good, reliable motors in those 5.3l LS based engines, but the 4l60e trans is unquestionably the weak point. Plan on about 100k out of the stock unit. If you can get one with a 4l80e (rare) instead, it lessens your probability of trans failures.
That's just one example, but every generation of every vehicle ever made has problems like that. Do your research and determine what you're willing to deal with down the road and financially plan accordingly. They all have their problems (Ford's 5.4l Triton is a ticking time bomb, and the Ecoboost isn't any better. The Hemi in the Ram is typically reliable, but they're comparatively WAY more money to repair when they do break down, there's lots of examples), it's up to you to decide what you wanna deal with.
EDIT: I would definitely check that truck out though, it's low enough miles and there's enough life left in the stock trans to not be nervous for awhile. Just save up and you can get a rebuild installed when it does go for not a ton of money. One of the beauty's of these trucks, they've been building them largely the same since about 99 so there's LOTS of parts out there for cheap for them!