the Lionel F3/F7 is a very good scale model in many aspects. I like mine a lot and when I get settled in somewhere I plan to "3-rail scale" them to the best of my ability...
C. Sam, You have made my point for me A VERY GOOD SCALE MODEL should NOT require a "3-rail scale" treatment outside of a Kadee coupler swap. The Lionel units require additional details to be added, ride height lowering (which is a nightmare to undertake), and fixed pilot fabrication. After all that, they still don't pull worth a darn. Now if your running them around the tree pulling 5 or 6 15 inch cars, then they are certainly capable. However, if you plan on pulling a long SCALE passenger train as SCALE diesels are intended to, you will find them incapable.
Now I know everyone thinks I'm some kind of lionel basher, but that's simply not the case. I have a large collection of Lionel Legacy steam engines and am a big fan of every one of em! Whistle steam is on of the greatest innovations in this hobby and lionel deserves full credit for it!
I just think Lionel is really laging in the "SCALE" diesel department, as evidenced by the defence of them in saying they will be run around the Christmas tree. While it's wonderful to have trains set up around the tree, SCALE diesels need to be held to a higher standard. If Lionel is mainly after the Christmas tree crowd, then drop the SCALE designation and go back to calling it O gauge. A SCALE diesel should have factory fixable pilots, easy kadee conversion, reasonably accurate ride height, and more than just generic details.
Those that are purchasing/preordering them on the premise that they are SCALE diesels as they are advertised are being duped. There are MUCH better SCALE diesels out there (3rd Rail). Those that just want something fun to run around the tree, will have exactly that. Anything legacy is fun to run, you'll hear no argument from me there. But from the original question, it seemed like Jeff T was concerned about detail and accuracy, hence my recommendation of 3rd Rail. Yes, I realize that this is the O/O27 form but most of the guys looking for better detail on a lionel diesel simply haven't found there way over to the dark side yet I was in that camp a few years ago.