The T3 Tactical has a 20 inch barrel, the Varmint barrel is longer.
The Tactical has a parkerized finish (including the bolt and bolt handle), the Varmint is blued or stainless. All T3s except the tactical have in the white stainless bolts and handles.
The Tactical's stock has adjustable comb height, the Varmint's comb isn't adjustable.
The Tactical's stock has sling studs on the sides, the Varmint doesn't.
Around here the blued Varmint is ~$600 and the Tactical is ~1100.
If you consider the stock upgrade is probably worth an extra $50, sling studs $10, parkerized finish $150, scope rail $150, threaded barrel w/thread cap $75, shorten barrel $50. That's almost $500. So, if you really want those extra features then yeah, its worth the money to have them all to begin with.
If you ask me the great majority of us won't need those features, so the Varmint is usually the logical choice. Of course logical never meant anything to most of us when buying guns