Well I had a 800GS, then later I went to a dealer with the intent on purchasing a nice 2011 Oil/Air cooled 1200GS. Liked it, but thought maybe I should go for the 800GS again...then dabbled a bit, then they offered a ride on a 1200GS LC. I rode it home with it 2 days later.
It's almost on 50 000km now (2015 model Trophy Edition)
No issues whatsoever.
If you don't have either the LC is definitely more bike in what some might feel important areas. Faster, more powerful, looks much much better imho (personal opinion), better lighting, better sounding stock, exhaust on the correct side, the clutch is easier and cheaper to access since you dont have to take the whole bike apart.
However, If you already had a paid off aircooled, to go and get the bits of extra power extra agility, extra looks etc - only you can tell. For some people some things are more important than others.
If you rode the LC properly you would know it's just much more fun to ride than the Air/Oil cooled.
Also for me the looks...

Where the oil cooled looked a bit old school odd.
Is it R160 000 better. I dont think so... but then you are also getting a new bike with warranty and and, for all that. So comparing an old bike 2nd hand with a new one is a bit of silly thing to do, since a new air cooled would have been much more expensive than your trade in. Compare your Air Cooled with a 2014 model or so LC with similar mileage and the price is much much closer and then I'd say yes it's worth the extra.