Look in the RealTracks folders how much recording there is.
The more you put in the better results. At the moment UTs transpose too much as it is to compensate for short usertracks.
I think they made it this way so users would not be put off by having to record a lot of material that realtrack artist are paid to do to make good realtracks.
So they are trying to put an option in like realtracks have "Don't Transpose RealTracks" to get better quality from longer usertracks, otherwise it just over transposes them and a guitar will sound like a mandolin in places.
RealTracks have the advantage over loops as there is so more diversity to choose from when generating.
If you use just a few chords in the usertrack recording it won't sound much better than using loops.