We had a similar dilemma with 19 vs 21ft...most of the time it's just the two of us so the 19 would have been plenty big enough. But since we boat in various waters we wanted more power and weight to cut the chop, plus the wife really liked the deeper cockpit of the bigger boat - felt more "in" the boat when cutting through waves and chop. And then there's the times we have family along and the added room is nice to have. Also the 212 will be better at making wake for boarding and surfing.
Oddly enough the twin 1.8L engines eats about the same fuel amount as the single 1.8L SC engine so it's a wash there.
This comes down to your personal needs and wants that only you can decide.
For us the 212 was the way to go as a 19ft wouldn't fit in our garage anyway. And when spending this much money on a new boat we figured we should get what we want and not settle. Kinda like buying a house, your first one is a settle, the second one you get what you want now that you know what you need.