Those are decent boxes. You'd spend a lot more than $1500 for a decent used box of that size around here.
I picked up the series 2 version of the 72" when they were on clearance when the 3's were coming out. I think I got it for a little under a grand. I ordered a top box at the same time and apparently they oversold those and mine got canceled.....which is fine because I really wasn't sure if I wanted it or the flat bench space.
I like the series 2 drawer layout better and that's why I jumped on that before they were completely gone. They made a big hype about the series 3s, but if you look at all the sizes, they all ended up with fewer drawers. The 2 had 18 drawers and the 3 has 14. Same overall volume, just fewer, but taller drawers. I tend to like more, shallow drawers. The did the same with the 26" set too - bottom and top each have 1 less drawer. I also picked up another one of those when they were clearanced. They had lots of shallow drawers and make great tooling storage.....closest thing that was out there to something like a Kennedy for about 1/4 the price.
I'd still buy the series 3 72" if I needed something today. You really can't get more box for the money anywhere else. If you don't need it right now, hold out until they do another 10 or 15% off any item coupon.
The layout isnt ideal, but I cant really bitch about it either.

