I went out & bought myself a so called "competition" filter basket but honestly I can't tell the difference in the dimensions nor in the taste of the coffee. In the pictures you can see the slight angle on my regular filter vs the straight & then rounded side on the competition.

I even looked at the holes under a microscope expecting the competition basket to have perfectly laser cut circles & for my regular filter to have jagged edged deformations, but very little difference.

I read that one should avoid the single-shot filters as they direct the water evenly through the puck towards the centre, which I can kind of understand. But in this case my conclusion is very little difference.

Any thoughts?

I've found significant differences in flow and resulting flavor (once dialed in) between tapered baskets and more cylindrical ones. Both can produce great espresso. "Even" the lowly, Faema-style, stamped basket can make great espresso. I've also found significant differences between, for example, the EPNW "precision" and VST baskets of similar dimensions, although they appear just about the same to the eye.

I have personal preferences among them, depending on roast level and my expectations in the cup and my conical grinder. Those with modern flats may have different preferences.

I'm much less convinced about fancy coatings.

The "competition" one looks different from side view, as it may distribute the water through puck better.
But I am in doubt normal people like me will see or taste difference.

Anyway I found some baskets are easier to knock out. I polished two of my baskets. One of them I am able knock out complete puck very easy. The other one (also polished) not so much. Different shape will have effect as well, so maybe this could be it?

James Hoffman in one of his videos also pointed out that better basket means better espresso. Maybe you catch his idea here:
http://www.youtube.com/watch?v=y1LUkfpTtu0

I have 3 different baskets for my Londinium R:

1. The stock 14-16g curved side basket that looks just like your quickmill one. Light roasts I can fit 16g in.
2. A EPHQ 14g basket that is actually closer to 16-18g. It's flat bottomed but with not nearly as many holes going to the edges as a competition basket
3. A 18g VST basket

I've done extensive testing on each. You know which one is my favorite? The cheap stock on that came with the machine. I like the smaller doses.

All I can say is don't buy into the hype of competition baskets. With a great grinder, capable machine, and most importantly, good coffee and skill, you're not missing out on much. Most flavor variations for me didn't come down to the basket type but rather variations in puck prep. Blinded, I couldn't pick one out from the other.

The only reason I see for competition baskets is if you wanted to use larger doses that are normal in the states today (18g+).