The Focus 2 ARF would be a good choice especially if you are just starting out...The new planes are suppose to be 10lbs on the 140Sport its great for a long time in your learning curve.
I think the ARC is around $600 and if you wanted a more dedicated model to work on with the glass fuse and all the Temptation kits are pretty good. I am helping a youngster with his and its good quality stuff. You can get the basic kit for like $650 or you can get one with the sheeted wings and and ailerons cut out for around $750...This is a little more than your goal price of 600 clams but on the other hand its a good flying model that has a proven lineage and will fly great on the 140Sport...From the looks of the $750 kit I think we are going to come in at right around 10lbs and this will be perfect for him...By the way he is flying Masters and will be using a 140Sport in it.

Troy