I currently have a 1995 4.3 liter V6 Astro with 130,000 miles on it, and it is in perfect condition. It has pulled a 9000 pound trailer across the country and up the mountains twice with no problem and power to spare. I now drive it every day and it runs like new.
The only big things that I replaced were the fuel pump at 90,000, the passenger door window motor, and an air conditioner compressor in the 15 years I have owned this van
I bought a 1999 AWD Astro with about 100,000 miles that appeared to be well cared for. I replaced the starter on it a week after I bought it (left stranded). I loaded it up with the family and a 4000lb trailer and moved cross country with no problems.
I later discovered that the glove box light switch doesn't properly align with the glove box door, causing the light to kill the battery (left stranded).
A year later the fan clutch went out during a hot and humid Alabama Summer day, overheating the engine, and taking the water pump with it (left stranded). The day after it returned from the shop, the alternator and battery went out while driving home from the Chevrolet dealership (left stranded).
Almost a year later (135,000 miles) and another cross country move (military) the intake manifold gasket failed (left stranded).
Six months ago (145,00 miles) the fuel pump quit (left stranded). The fuel pump relay switch quit a week after that (left stranded).
Today (150,000) the check engine light came on, Mechanic stated that the O2 sensor was shot, and oh by the way your idler arms are shot too. I have owned several vehicles with various mileage, and I have NEVER had one of them leave me stranded. I am not surprised that GM's business is failing. I am currently wondering how much of a trade in value my Astro will afford me towards a Toyota.
My spouse bought a 1991 GMC Safari after she drove the Astro van for her company. She is an investigator, and puts a lot of hard miles on her vehicle chasing bad guys. Last check she had more than 280,000 miles on the vehicle, but was forced to retire it after it was hit by an errant police cruiser. Her previous company put their investigators in Astro/Safari vans, hers was a hard running machine, but as others have said, you must keep up on the maintenance. I can't vouch for the later year models, but the early 90's vehicles seem to be real troopers as vehicles go. I really like the truck rail construction, the machine has a little meat on its bones.
Although I've never owned an Astro van, both my cousin and neighbor have. Both were very happy with theirs and never had any problems. My cousin drove his just over 200,000 miles before trading it for a Ford, and my neighbor actually got just a few miles over 300,000 miles out of his. He is a mechanic for a large company that refuses to use anything but domestic vehicles because they are so much more reliable. He now drives a Chevy Trailblazer that has performed flawlessly for over 100,000 miles without a single repair. Most GM vehicles will last a VERY long time if taken care of.
Astros are great vans. Sure, GM vehicles have a lot of small breakages like interior parts and window motors.
They require regular service, but are popular with their owners because they have great interior space and are built on a strong truck chassis.
They are also the safest vehicle on the road (fatalities per millions of miles travelled). The government gives them poor crash test ratings, but in the real world they do very well in crash survivability. I would rather be driving a high riding Astro van than a smaller front drive vehicle in a collision.
Buy a Ford or a Chrysler van and you will be repairing cylinder head gaskets and major drive train components.
The window motors have way too much grease in them from the factory. It gets into everything and burns the thermal breaker and the brushes. Brushes may be worn too. The whole assembly isn't too expensive, but you have to tear the door apart and drill out rivets to even get it out.
The windshield wiper issue is common on GM trucks, and the fix is easy, and cheap. I have a '92 Sierra that had the same issue, and the fix was to repair the cold solder joints in the circuit board where it bridges to the wiper motor assembly. Over time, the solder joints develop tiny cracks that can be seen if you look very closely with good lighting, and perhaps a magnifying glass. Even if you can't see the cracks, it doesn't matter, it is likely the issue. All you have to do is resolder those joints with your soldering gun and solder. Literally a 5 cent repair, and done in minutes. Wipers now work perfectly.
Those vintage of 4.3 Chevy motors have no balancer shaft, so they tend to have a rough idle as a result. Much of it is due to the fact that this motor is essentially a 350 small-block Chevy with two cylinders cut off to make it into a V6. Nature of the beast. If it runs strong and smoothly off-idle, I wouldn't worry about it.