Q:

How reliable or trustworthy are LTSPICE demo circuits?

I'm looking at a few switching power supplies and one of the demo .asc files for the particular controller I was looking at really seems to fit my requirements. 
Can I use their schematics in designs as is or are their some hidden 'gotchas' between what they demo vs real life ? 
Edit
The controller I am considering using is the LT3748 and the LTSPICE model I was looking at is LT8309 & LT3748 Demo Circuit - 60W, 12V Output, Isolated Telecom Supply (36-72V to 12V @ 5A
For those that do not have LTSPICE and just want to see the schematic

A:

According to my experiences, all simulator are just simulator, they rely on how precise your models are, and how precise your circuits are, such as if you take all the parasitic factors into consideration. This is particularly true for power supply designs.
In my opinion, LT's demo design (not just LTSpice demo circuit, i mean demos with demo board) usually have high quality. So i recommend you to reference their demo boards design. I think them are more reliable than the LTSpice demo circuit.
In your posted .asc file, you'd better go to the similar demo board: DC1961A - LT8309ES5/LT3748EMS Isolated Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A.

Update:
I don't mean simulator has no use, they are very useful indeed, they can help you to verify your ideas before throwing so much money. But if you want to find a reliable reference demo, demo board may be more reliable.

