I use this exact recipe! Sometimes I add a little bit of cream cheese (and I even use the cheesecake flavor sometimes) and it is great! It doesn't really change the consistency - I get perfect cookies every time. Firm enough to handle but soft and delicious inside!
I have been topping mine with pre-cut modeling chocolate - I put it on as soon as they come out of the oven and it "melts" into the cookie but doesn't lose its shape - makes for a beautiful, well-defined decoration without piping - and everyone I know LOVES modeling chocolate -way better than the fondant (even though mine is pretty good)!