What sprockets/chain set do you run and why?

Ditto....But I use the x-ring chain they offer.
Paw Paw

I run the TAG Metals rear sprockets. They're hard-anodized, so they wear much longer than a typical alloy sprocket but are still very light. Stock front or a Renthal Ultralite. I use a base-model Regina non-o-ring chain.

Keep the chain adjusted and arrow-straight on the sprockets and your stuff will wear much longer also.

I use the Rehthal aluminum rear, steel front and a DID chain…. Interestingly enough, I told the guy at the parts counter of Thousand Oaks Powersports that my chains seem to wear really quick (Gary, long time employee and trackside BlueCru mechanic), So he quickly asked are they Renthal sprockets? I say yes and he tells me "Yep, I knew it". He goes on to tell me that many customers had been telling him that the DID chains were wearing fast (paired with Renthal sprockets) and he decided to ask the Renthal rep one day. The rep explained that the Japanese chains don't really fit the Euro sprockets and the tooth size ratio (while still 420) were not the same. He said use a Regina or Renthal chain and the problem will stop.

I said F it, I'll go back to the Mika stuff is was using on smaller bikes with awesome results!

Your sprockets will last long time if you keep a fresh chain on like that guy up there posted.

I used the cheapest aluminum sprockets i could find,like magnum .

And used o ring chain and never ever pressure wash it.

I also kept gear sets for mud races,a worn chain and sprokets that I'd switch out before either muddy practice or if it stormed,already set up to get maximum wheelbase for stability and 2 teeth smaller on the back to make gears longer and kill some torque.

I've tried about every sprocket out there (almost) the ones that stick in my mind as the most durable in this order =
TAG, Sunstar Works, Renthal. Definitely not Pro Taper, it seemed to wear rapidly. I currently have the twin ring Renthal, good, but for the money, nah, it's wearing too. DID on the chain. BTW, this is for YZ450F.

Sunstar front and rear with a gold protaper chain. Sun star sprockets are OEM quality, a little thicker so the chain ride flat. Plus the fronts are coated black, they look cool.

I just installed a set of the PD and they fit like a champ
- the best part is that the chain came cut to oem spec

And was 100% free with all the rm/ atv race gas gift cards I had laying around.

I am cheap! I like nice stuff but don't like paying top dollar for it. You asked about iron man sprockets and I have several years experience with them. Top quality product and light. We moto guys always stress over our bikes unsprung weight and that would rule out steel sprockets except for these they are light. At $110.00 this sprocket seems expensive but will last at least two years if you use an oring chain. I run the regina orn6 $ 90.00 . With a renthal or any other aftermarket sprocket running $60.00-70.00 and lasting only a few months on a 450cc bike the ironman is a great bang for the buck .
Another great oring chain I like is the RK GB520MXU , it is not as wide as most orings and a little lighter if weight is an issue to you.

Renthal front and back with DID ERT chain.... looks good and last reasonably long!