Exactly why i bought new last week,ok the facelift is out in march but i got the model/colour/spec(and more) i wanted at close to 20% discount(£41k list-after dealer contribution/finance for 2 months it cost me £33,100).
My wife got an SLK200 on Agility a couple of months ago, on a one-off deal- I reckon the total cost of ownership over 2 yrs will be around that of a 2 y.o. Used Approved example. Which wouldn't have had the colour combo she specified.
Even when new comes at a premium, it might be worth it for the peace of mind of full warranty- and particularly the assurance that you've not inherited a time-bomb caused by the previous owner's engine mods.