We usually combine our trips to WDW either with going to Sarasota before hand or after WDW. We have even traveled from Sarasota to WDW for a 1 day visit during our beach vacation there. Travel time is about 2 hours, unless there are any major delays on I-4 (think this is the name of the highway leading to WDW). It's a nice ride.
I have family in Sarasota, but we actually stay on Siesta Key. This is a nice barrier island with a gorgeous public beach. They have the most awesome white, powdery sand that is claimed to be the whitest in the world outside of a beach in Australia I believe. However, there really is no surf here, and I just love floating in the warm ocean without floating away with the current most of the time. The water is so clear, and dolphins can be seen most days. We have swam around cow rays (thought they were stingrays!

), and saw a manatee. It is a tradition of the vacationers there to sit with a beverage and watch the sunset-not to be missed!
We have always stayed at Siesta Sands on the Beach. I believe it was housing for the city workers at one time, changed to condo units, each with it's own owner and decorating style. There are definitely not any amenities here. No pool, hot tub, free shampoos/soaps or activities, but they are right ON the beach. You might be looking at something much, much more upscale by looking at your other choice. We have been there when there was literally water up to the retaining wall of the deck (1987), but for the past visits over the last 12 years, we had a nice stretch of beach and some sea grass just out of our door. It isn't the type of place for everyone, but the LOCATION can't be beat. We have enjoyed being able to watch our kids swim, play in the sand, 4th of July boat races and making new friends on the deck while toasting to the sunset.
Nearby in Sarasota you have the Ringling Museum, Selby Gardens, St. Armand's circle, great artsy shoppes, and wonderful restaurants, among much, more. We haven't been in a couple of years due to spending some longer trips at WDW instead, and teens costing us much more money than they did when they were small, but hopefully next year it is just Siesta Key! It is an hour away from Busch Gardens, which we also enjoy very much.
Not sure if you are flying, but we have flown into MCO and returned out of TPA since it is only an hour from Sarasota. Sarasota has a nice airport also (SRQ), but can be a little harder to get airfare comparable in price to the bigger airports. Hope this helps a little! I can't speak for your original plan, as I have not been there specifically. I love, love the gulf coast though!