in general...
If the base coolant is the same, as in "long life" in red, then its fine to mix brands.
I generally tell customers:
if red use red, orange, pink.
if green, use green, yellow, neutral.
I use Penrite.
I also buy premixed, which is what I advise customers to do.
While concentrate is cheap cheap to buy, you still need to use distilled/de-mineralised water, labour and mix it in the correct ratio.
I'm sure that some just use tap water which then negates any properties the coolant has with regards to corrosion protection.
Also remember coolant is Ethylene glycol based (like brake fluid) and toxic for both animals and the environment.
The actual base coolant that oil blenders and such buy come from two sources that manufacturer the base coolant. Caltex and Chevron.
