http://www.oemantifreeze.com/oem-blue/

Purchased this coolant from Pep Boys last year. I purchased the concentrate which is meant to be diluted 50:50 with distilled water. It was around $12/gallon so about a quarter of the price of diluted Honda coolant with shipping. I wanted to flush the system with distilled water which I can do with the concentrate. Looks like it is equivalent to Honda coolant.

Anyone have experience with this product?

It is good stuff! You can use it with no problems

Some advice with concentrate coolant that you have to add water yourself: mix the water and coolant before pouring it into the radiator! You can use the water jug for this. And also, the Lisle coolant funnel is awesome.

Other good choices are the blue Zerex Asian they aell at Walmart, or Pentofrost A3 from AAP or Napa. The A3 is the actual OE coolant and made in Japan. However, both the Zerex and Pentofrost are 50/50 premix

AZ has a new line also, the manager was telling me his product sheet shows it being made by Pentosin. True or not, I have no idea.
They are using the same label colors as OE on the black jugs.
It doesn't come up on their website so it might not be in every store.

No experience, however it is made by Recochem and like Type 2 is a long service interval Asian PHOAT AF. And as you note, comes as Concentrate making it perfect for a complete flush/exchange when used with distilled water. For $12/gallon, an equivalent premix would need to go for ~$6 to equal it. And premix not well suited to complete exchange. I'd use it with confidence. I believe it's getting harder to find at PBs now.

Why do u recommend mixing before pouring into the rad? When I do full coolant flushes, I just pour concentrate coolant directly into the rad at 1/2 the capacity of the cooling system, then fill the rest of the way w distilled. Never had any issues on GM, Toyota, etc that I’ve worked on

That's the only way you can do it unless somehow you know the exact amount of water remaining in the engine after flushing. If you pre-mix the concentrate how do you know what concentration to mix it at to end up at a desired concentration in the engine allowing for the remaining water?

Even if you know it would require a Laplace transform or Bessel function to get it I think

Easy enough to find out the cooling system capacity from your manual or from an internet search. I have a Honda K24 engine and the specified capacity is 1.9 gallons. When the system is drained from the petcock I collect just shy of a gallon of coolant. To fill the system it takes exactly 1 gallon volume.

I am going to flush the cooling system with 4x1 gallons of distilled water, running the engine for on each flush. The remaining water should have around 3% old coolant and a .9 gallon residual remaining volume. I will fill the system with 1 gallon of concentrated coolant when flushed and check with a hydrometer.

In my opinion having concentrate and flushing with distilled water is a great advantage. When manufacturers went to 50:50 your cooling system was only partially changed. In my case around 50% was old coolant.