Sig Kadet LT 40 ARF
The extra $100 it will cost you will be very well worth it. It is a very nice looking plane and I can not wait to fly mine this spring. As mine was not an ARF it was also a very nice build.
I would definitely go with the LT-40, you won't be sorry.
I have heard from others that airplanes such as the Hangar 9 P51 Mustang PTS and others of its kind are very poor choice for second plane. A low-wing trainer would be a better choice for a 2nd plane.
Just my 2-cents worth