We're members, have been for YEARS. It's not for someone doing minor projects or only need a new couch. We did a major home remodel about 6 years ago (totally gutted a house and added a full second floor) and we saved about $30,000 by using Direct Buy. We bought A LOT of stuff from them - everything from tile to fixtures to lighting to the furniture to furnish the house when it was all done. Major, major savings.
Now we're in a new house and planning another major remodel. I'm thrilled I kept the membership because I plan on using them extensively again.
It is a super high-pressure sales pitch. They basically say if you don't sign up RIGHT NOW, you can't come back. You can't go home and think about it overnight - you're expected to make a decision right then and there. It's not for everyone and most people are turned off. I was, too, until I started actually comparing the prices (see next paragraph).
If you DO go for a presentation, make sure you have a list of the exact things (down to the model number so you're actually comparing apples to apples) you're PLANNING TO BUY ANYWAY and find the best possible prices for those items on your own (through online or Best Buy or wherever you'd be getting those things). Then at the presentation, you'll get a chance to look through their books and see what the DB prices are for those things. Be aware that there are handling fees, etc on top of what the prices are, though, and factor that in. When we went, I had a list of appliances and furniture I was going to get anyway for our remodel. When I did the math, we were going to make back our membership fee on the fridge and couch alone. For us, it was a no brainer. And like I said earlier, we saved around $30,000. I price shopped every item, every faucet, every recessed light fixture, every can of paint, everywhere from Home Depot to high end design centers, everywhere. I saved on almost every item over trying to buy it myself (or even getting my contractor to buy it with his discounts).
But if all you need is a new couch, it won't pay to join.