Objectively, NT neck (never a costly reset), cutaway and electronics together might add $500-700.
Quality of woods, bindings, etc. might add several (or more) hundreds.
Subjectively, playability (action), tone, feel, etc.
If you add all the above up, and it doesn't total the difference in your mind, sell the Taylor.
I suspect that your problem right now is just a case of normal "buyer's remorse."
Give it a month and see what you think. If you are picking up the Taylor more often than the Yammi, your question is answered.