I purchased 2 of these and linked them together.  (Note that in the photo they are covered in pollen; the finish is not worn.) They were just what I needed.  The tops are easy to screw off to drop a pump/mosquito dunks/etc. into the barrel.  The plastic is sturdy but was easy to drill through to connect the first rain barrel to the downspout diverter system. I recommend that if you are going to link them to purchase a hose length of about 2 feet so you can position them the same way next to each other.  (I had a 9 inch hose and so I am unable to have both valves facing out as a result.)  When the barrel is full the water will shoot out the bottom valve straight, so you may want to add a piece of piping to aim it downward (or just have your bucket or watering can placed far enough away to catch the water like I do).