This is a gravity fed distributor, which means that instead of having an adjustable depth that you have to faff around with to make sure the depth is just right, the spokes just drop until they hit the top of the coffee.
Features and Benefits:
• Four spoked distribution tool
• 304 stainless steel spokes
• Aluminium outer
• Size: Available for portafilter sizes 49, 51, 54 & 58mm
• Gravity levelling
As far as distribution tools go, I do like the gravity fed versions. Whether you'd be better with gravity fed or adjustable, really depends on who you speak to, for me the gravity fed options are just a bit more convenient.
Do you actually need a distribution tool, nah, not really. They help to create a level surface, there are various ways to achieve this, but they're a convenient approach, and each to their own, but I really quite enjoy using these distribution tools.
If I have the time and I'm not in a mad rush, I'd prefer to use every tool I have at my disposal ;-), because it's fun. Take them all away and in reality, most people are unlikely to notice much (if any) difference in the cup, but espresso isn't only about taste, it's about experience too, and if you don't agree that's absolutely fine, don't bother buying one of these.