I've only used Sears and had good experiences both time - I do get a bit obsessed and bring in my own props & tell them what poses I want (they probably smile when I leave) but the pictures have turned out great. My sister has used Kiddie Kandids with great results & if we had one here I would try that - I think her pics were quite a bit cheaper and they came out really cute also.
Re: protrait studio advice!