Gentlemen, what is the difference between firmware V6 and V7, which is better?

first, v7 has a newer and more feature rich kernel

but as always - it depends.

e.g. i am running v7 and v6 in prod environments depending on the situation. dependent on where which device gets deployed. (60/5GHz PtP backup link for example runs v6 on to occasions)

Gentlemen, what is the difference between firmware V6 and V7, which is better?

better?

Gentlemen, what is the difference between firmware V6 and V7, which is better?

For basic stuff like home router better to move to 7. For advanced like MPLS VPN4 etc better to stay on 6 yet because still a lot of issues not solved. But it is also depend . Some function works good some features in ros 7 is complete disaster.

Gentlemen, what is the difference between firmware V6 and V7, which is better?

You may read changelogs about the differences. I prefer not to upgrade to V7 devices which works well on V6.