You should definitely talk to this guy before you decide who to use. Really knows his stuff. There are a lot of landscapers who will tell you all sorts of bs and there are a ton who really don't know what they are doing. With a project that large, I would talk to a few people before you proceed. He is helping me rip out a botched landscape by the builder.
outdoor life landscaping- Bill
Outdoor Life, Inc.
Also maybe talk to Exotic Landscapes in Fort Mill