I'd think very carefully about your interior layout and space requirements before buying an astro. If it will work, that's fantastic because as T.Low and others have said, it is a great driver and very capable.
For me, i think it's too small. I have one that i drive every day for work, so i am familiar with the van. It's only about 7 feet from the back of the drivers seat, to the rear doors. I like my bed to be a few inches longer than i am, that means that the bed would take all but 6 inches of the interior length. The roof is also fairly low, which means you can't make a seat or bed platform very high, and also, for me (6'1") it cuts my visibility relatively low out the windshield. It's not uncommon to have to duck my head down a little bit in order to see up to a traffic light.
If i sound awfully critical, it's because i'm bummed. I'd love to use the astro for my camper van rig, because it's small, relatively efficient, cheap & plentiful on the used market and because they are easily modified for pretty good off-road capability. But i just don't think i'm going to be able to do it, it's too small for the kind of traveling that i want to do in it. If you only want a very basic interior, it will probably be great. Also, adding a pop top can change the picture quite a lot, because then you don't have to figure out how to make a sleeping platform inside the van.
In any case, by no means am i trying to talk you out of it. Just speaking as an owner of an Astro, to let you know that you should plan carefully for the available space before pulling the trigger on a purchase. It may well be the perfect rig for you.
For me though, it will probably be the AWD Express van, and i'm really, REALLY hoping a suspension lift solution can be created for that, similar to what is done with the Astros.