I am going to tell you my opinion on Seralago...The hotel has gotten more good reviews than bad! The hotel is renovating rooms, but it is going slowly. If you stay there, make sure you request a deluxe pool room that has been renovated. If you are interested in Champions World, the site shows them at 3.5 stars and a price point of $30 per night. I did a reservation for me for 8 days and it was only $283.00 for all 8 days!!!! that's pretty good if Champions is what you want. If you want help with planning and finding prices, private me and we'll talk! Check your private/conversations on your profile...I left info there!
We have stayed at Champions World and we really liked it. The rooms were very clean, one of the pools is covered and the little path around the lake is beautiful and relaxing. The only minus was the distance from the parks .
Seralago on the other hand is in the middle of everything. Close to the parks and minutes from Old Town and any chain restaurant you can think of.
I'm sure you will enjoy your stay no matter what you decide.