Am thinking of traveling to Sicily and have checked out flights to Catania and Palmero. Flights to Catania are much cheaper. Is there a huge negative to flying there?

It depends on what you want to do in Sicily. If you are planning a trip around the island, it's pretty immaterial whether you fly into Palermo or Catania.

If you are staying in the city of arrival, Palermo has very many more points of interest than Catania.

Catania gives you access to eastern Sicily: Taormina, Mt. Etna, Siracusa, the Baroque towns of Noto and Ragusa.

From Palermo, it is easier to reach -- if you have a car -- Erice, Segesta, Selinunte and Agrigento (which is also accessible by public transport, as is, I think, Piazza Armerina).

I have booked flights between Rome and Sicily for October; I have not found that flights to Catania are "much cheaper"...