Well obviously it's ultimately your decision as a developer, personally I prefer to have my games over steam for ease of use/access (and I hope Lancer Tactics will be published there, because proper mod/workshop support could extend the game's longevity tenfold).
I am itching (pun somewhat intended) to play the game, but at the same time I'd rather wait out for the Steam release and buy it there directly unless there is an official statement about itch.io purchases being transferable.
Also, do consider that even with the Steam price at parity, if the purchase is transferable you can still encourage people to buy on itch.io to get the larger cut of the pie.