Alex wrote:

I have an opportunity to buy high quality drill bits really cheap.
But since I already have a bunch of cheap Chinese bits from HF and I am
pretty much satisfied with them so I wonder if I even need these hight
quality bits. I remember reading on this forum about big difference
between good bits and cheap once.

I can tell you what I think the difference is.

With a cheap drill, the first time you drill
a hole in steel and let the steel work-harden
before you've finished the hole, you've dulled
or destroyed the cheap drill.

Quality drills keep going and are far more
forgiving of drilling in a work-hardened hole.