I am a fan of the Hornby Railroad range. I wondered if a direct comparison of the RR Vs full fat version of the same model would be productive. The model is a maroon MK1 TSO in maroon, see the shots below.
The RR ones were <£20 when I bought them, the full fat versions now seem to be >£30 a piece.
In summary, the only difference that my untrained eye can see is the extra transfers on the full fat version: on the windows, sole bars and ends. Easily and cheaply addressed. Oh, and fancier packaging.
The finish on both is excellent, although the lining on the RR is a little more subdued, which actually looks better to me.
At normal viewing distances they are almost impossible to tell apart.
These days my philosophy is to ask if something is "good enough", having abandoned the pursuit of perfection due to a lack of time!