I have only owned my Astro for about a year now but for the most part it has been very reliable. I bought it used and had to put a new rear end in and now the fuel pump went out. As you may or may not know Chevy has internal fuel pumps that are a complete pain to replace. The only other issue turned out to be that the transfer case fluid needed to be replaced (I thought it was going to be much worse because the front end was binding up in turns). Anyway, these are the only issues I have had and I love the van but I am selling to buy my son (turning 16 soon) a more age appropriate car. I think the van is cool but I am old I guess!
Overhead display, although when I first bought the van this distracted my simple mind causing several altercations with my wife! Rear heat and air for the kids
Better fuel pump design better transfer case fluid some way of keeping rust off the bottom right side of the rear window. I have noticed that about every older Astro has this rust in the same spot.