It all really depends on what you are wanting to do with the rifle you are putting the barrel into
I have had some really good PDI, laylax, Madbull, EdGi, and DB custom inner barrels. And all of them were different lengths, from 280mm out to 575mm, as well as different inner diameter.
They all worked and they all didn't work. Like I said in the beginning, it all depends on the system that the barrel is in, and how you are wanting to use it.
And the other thing that you will have to consider with a question like this ....... is that every one has a different set of "what is good, and what is crap". Everyone is going to assess the barrels differently.