What sorts of things do you look for when trying to pick a preschool for your LO? Ratios? Educational philosophy? Facilities? Location?

We are trying to pick a new school for LO1 and I am having a tough time narrowing down what is really key for me. I also love his current school so am comparing everything to that...!

(I am a SAHM so we are only looking at part-time programs, so things like hours/full day care are not necessary).