You're not talking IPS until you get over about 36'. Below that you're probably dealing with Mercruiser Axius system.
The pods, especially the IPS, is the future of boating. Putting aside the maneuvering & speed advantages, the fuel savings have to be a huge consideration.
Comparing Formula to Tiara is comparing apples to oranges. Tiara is much better quality, Formula is glitzier and with a much lower price. Both are fine boats though. What you have to consider is how you will use it, how much, and for how long. Will you spend your time cruising Peconic, maybe shooting over to Conn. or will you be running to Newport and the Vinyard? Are you looking for something you'll be selling in a year or two or that you'll be keeping longer? Will you be bringing it south for the winter? etc.
I'm an independent captain and spent the last couple of days transporting and teaching on 31 & 35 formulas, while that Tiara with the IPS was being demo'd. Very familiar with these boats & more, as well as the dealers in this area and the waters. PM me with more info on how you see yourself using the new boat and I'll help you to narrow the decission.
P.S. There's a better than even chance that I'll be the guy who ends up teaching you how to run your new boat.