Your description is spot on. JTCS is the next step up in the scale chain from Squad Battles.
In SB the squad/half squad objectives are buildings, crossroads, bridges, etc. In JTCS it is towns, and battle areas that include bridges, etc.
JTCS is really suited for up to Division level combat but, in my opinion, that is pushing it. Six minute turns and 250 meter hexes seem more fit for Brigade/Regiment size battles.
It is an ideal game at battalion level with about an hour or two of fighting.
If you are a gamer and already like SB you cannot go wrong with JTCS.
“The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane.”
― Marcus Aurelius, Meditations