I've carried both longer than some people have been members here.
The k390 predates the use of the 15V in the knife industry. So obviously, I was a big fan of it and it's what led to me working with 15V.
I've certainly noticed over time the a11 class of tool steels has shown an extraordinary level of strength, stability and edge toughness for what they are when heat treated, processed and sharpened appropriately.
The 15V has always represented an extreme of that with the additional 5% carbide volume. 15V also being at the absolute limit of vanadium that can be commercially produced by a steel company since 18V and 20V weren't able to scale up from lab melts.
The 15v is less reactive when carried over a long period of time.
I have a k390 pm2 that I didn't use as much as the 15V Manix 2.
In my experience, the edge came up crisper on the BBB 15V vs the production K390 and I could push lower edge angles with more stability. The caveat though is that bonded Diamond and cBN is key to unlock the highest performance but the reward was you could sharpen when you want to not because you had to.
Once the extreme sharpness died off it could rest on its working edge for quite a long while which then could just be maintained with diamond/cBN compound on loaded strops for an extremely long time.
A note, most of the mass production k390 will trend softer than the 15V.
I'm not trying to change the op's mind on which is better.
You can't lose when you're making a decision between those two steels.
Both are very enjoyable.
Good subject.
