I run and play both.
The theme/setting/genre is very similar for both but Trail probably leans a little more towards the Pulp and of the spectrum but both ToC and CoC have specific Pulp variant rules that make the players tougher and more heroic...
Call of Cthulhu is the original and the big daddy in its genre.
I probably shouldnt say this but I tend towards liking ToC more due to the way the rules specifically assist investigation whereas the CoC rules can be a little arbitrary. A good keeper will ensure you have multiple opportunities to find the essential clues while in ToC you will always get given the absolute essential clues.
CoC on FG is definitely a much more robust and polished product than ToC is.
If you do give ToC a run also have a look at the MoreCore+Extension I linked above.
Ive also played+run ToC using this ruleset but I think a few errors have crept in as CoreRPG has evolved.