Here are what I see as the major advantages of induction:
1) MORE POWER: An above-average gas top big burner will give you about 15,000 BTU's - a large induction burner should give you around 28,000. That essentially halves the amount of time it takes to boil a pot of water and just as importantly return your pot to a boil after adding what you are putting in it.
2) MORE EFFICIENCY: 80% of the energy created by a gas top stove is lost into the air. 90% of the energy created by an induction top goes to cooking your food. Remember, an induction stove heats your pot, not the surface of the cookstop. (This also means that you aren't pouring tons of heat into the air during our lovely TX summers which keeps your house much cooler during cooking.)
3) MORE ACCURACY: Induction is automatic on/off just like a gas cooktop and also the instant range of heat - it allows you to have very small amounts of consistent heat as well (i.e. you can cook chocolate or an egg-based sauce without using a double boiler).
That being said, induction cooktops vary in quality/power just like gas cooktops do and you generally get what you pay for. If you already have the pots/pans that work for induction you are most of the way there.