OK, I fly them both. The 120 is faster in the cruise than my 206's, by about 12-14kts. Some are smoother, one around here vibrates like a 1950 washing machine. Eurocopter have given up, and are replacing it for the client. Power wise, no better than my 206's: RoC can be 2-300fpm less than a similarly laden 206. General handling, the 120 feels more skittish, the 206 more stable.
Worst thing about the 120, the low inertia rotor system. The dead man's curve is down at about 10 feet until >50kias, and you need all the momentum you can get. The 120 comes out of the sky like a heavy R22, and has probably less left in the rotor at the bottom of an engine off

Hold the flare until you can count the blades of grass, wait another millisecond, and hope that you've got it right
😱 Eurocopter allow run ons at 30+ knots, and for a very good reason: chances of a hover auto are slim to poor. I would hate to be doing a low level film job, and have to auto in with any degree of confidence. The 206 is a delight in comparison, and gives stacks of confidence to any low level operation.
The cabin of the 120 is excellent, although the seats are not as comfortable for a long day as it initially seems. Passengers love it, though, and rightly so. Baggage space in the boot is great, the split fuel tank is weird: half above the boot, half below. The fuel indication hangs up until the sensors work out that the fuel has drained out of the feed pipe between the two tanks.
Endurance is the same as the 206 with a range extender, fuel burn is up about 25-30%. The clean exhaust is nice (no washing sooty tail booms), but the long term overhaul costs on the engine looks awesome cf. the C20. No spare space in the radio stack to put tactical radios, they have to go on the instrument panel.
All in all, currently no reason (especially financial) to change from the 206. Once 2nd hand market prices start to even up.....maybe
😉