In which city is the alt upgrade more balanced?

Demons in Inferno. The old ones were useless... until you get to them.
But a jump is a different story. An explosion can't compete with a jump.
Also, the new Cerberuses have a significant advantage: they are the same as the old ones, but even better thanks to the fire damage.

However, I didn't really like the jump ability. It's useful against archers, no doubt, but in any other case... What do we get by jumping on a group of heavily armored units? Almost nothing, except for a brutal counterattack. Unless, of course, there's a way to absorb the counterattack with a summoned unit. And in the endgame, they can be useful, since demons are expendable; you don't mind sacrificing them, and they can deal a lot of damage, even if it's just once.

As for the Cerberuses... If you're confident that you'll be able to upgrade them in the future, take the old ones; if not, take the new ones right away. Even though many of the demon upgrades are still the favorites in most cases, there is some balance.