This is just MY opinion.
I bought my 04 Envoy almost 4 months ago from a a large dealership. Now even though my fluids looked new, this truck was not taken care of by the previous owners. I have had all sorts of issues with this truck from day one. I will fill you in on what we have had to do to my Envoy.
1. First day we got it home, the heat wouldn't work and it was probably 5 below(Bought it in Jan) Found out the blower motor took a crap. It worked sporadically when I test drove it, so I didn't notice anything right away. My warranty covered the parts and labor.
2. My fan clutch was diagnosed as taking a crap the same day I had the blower motor fixed. I haven't replaced it yet because I'm doing an e-fan kit.
3. Found out after coming here that my Thermostat was dead. It ran around 160-170 on the gauge, and even colder on a scan. So we replaced that.
4. A week later, maybe 2...my power steering pump went out, and I had to drive it for 2 days without power steering while waiting on the part to come in.
5. Hearing a clunking sound from the truck on turns and hitting bumps...needed to replace sway bar end links.
6. Needed to do a coolant flush because the dexcool had turned gooey and seemed to be not flowing like it should have been.
And a few things we have been dealing with that popped up after we bought the truck....
1. The filler tube in the gas tank causes the gas pump to shut off prematurely, and I have to wiggle it to get the fuel to pump properly
2. Need to change out fuel filter
3. Spark plugs(done)
4. Brakes and pads
5. Wiggly drivers side view mirror
6. Lights on the radio and other components do not work and need to be switched
7. Did an oil change and found they were using a really shitty Chrysler oil filter which wasn't the correct size
8. Someone at the dealership rammed the passenger side front fender into something and caused damage resulting in needing a new front fender
I'm sure once I get all these things taken care of, some other crap is going to pop up needing to be done.
I also had to do an oil flush and clean the CPAS after hubby added engine restore
Buying any vehicle that has not been loved or taken care of by the PO or the dealerships can be a pain in the ass for the rest of the trucks life, or until you get sick of fixing something every week and sell it or trade it in. But in the end, when you sit in the drivers seat and feel completely confident and safe in the truck, it all makes it worth while. I have never felt more comfortable with any vehicle that I have ever owned. Safety was a number one concern for me with a vehicle, and I have never felt safer. Reliability was the second most important thing to me as it is my daily driver, and even though my once unloved Envoy has issues, it has yet to fail me unlike my previous POS.
I'm sure if you already own a TB or Envoy you know what it's like to be an owner/driver. The way I look at it is this.....
IF you can afford the maintenance and the little surprises the truck will most likely throw at you, and if you can take the time and deal with the frustration you may have on a daily basis for the trucks entire lifetime, then go for it. I have never been in love with a bigger POS than my truck, and I wouldn't want it any other way. I have learned a lot from buying my truck, and I don't think I could ever NOT own one. If this one takes a shit I will get another one, but not before I did everything I could to fix the one I have now. If I totaled it today in an accident, I would buy it back from the bank, cut my losses and fix it up. I have owned many cars, and hated every single one of them, but there is just something that is irreplaceable in the Envoy. I would rather buy something that needs work, then something that was perfect right from the "new car" lot.