I personally am not a fan of any bases. I liked having a removable wood countertop placed over the washer dryer. It gave me more surface space. Bases are rarely tall enough to store anything useful. Plus, those of us who've done the front loader thing and now loathe them didn't waste the cost of having bases and have just an even floor on which to place a new He top loader. That's another issue though. I say removable top because every now and then those control panels got wonky and I had to access the outlet. So sliding the top up and out a bit was necessary.

We recently added a wood base to ours, and we've had no extra noise. I love the space to put 3 baskets, and it has been GREAT for my back. :) The surface space on top was nice, but I find this is a bigger help than that was. I have space next to the machine in our new laundry room, so I don't really need the top. (Plus, it can no longer collect clutter. Haha!)

We built a frame and tiled it. Had I seen young gardener's picture, I would have stole that idea! Agree that it saves the back.

Wood is much more flexible than the metal bases and if you choose to do a wood platform, it should be made about twice as sturdy as you think you need it to be. 2 layers of 3/4" plywood on top of 2x4's used vertically as "stud walls" rather than horizontally should just about do the trick.

A platform will make it much more difficult to service the machines and to do the semi annual cleaning of your dryer duct that should be standard homeowner maintenance. When the machines are mounted on the individual pedestals, they move as a whole to slide in or out. And the washer weight is in the neighborhood of around 200 pounds. Only Samsung and LG have seen fit to put hand holds on the sides to make moving them around easier to do. All of the other brands assume that you have a body builder living in the home.