Noah Andre Trudeau came out with a book on Gettysburg about the same time as Sears did, and I think his is a little bit better. Regardless, either one would have done a better job than Goodwin.
Trudeau's book was excellent especially with regard to the first day. I think it would appeal more to the hard core CW buff though as it is incredibily detailed and the average history fan might find it a bit tedious to slog through. There is another historian named "Rhea" who has an excellent series on the battles which made up Grant's Overland Campaign.
Not to toot my own horn, but I met Trudeau several years ago. He was doing research for a book on the 55th Massachusetts Volunteer Infantry. He’d heard I had done extensive research on the unit. I provided him unlimited access to my records, and in return, he gave me a very nice acknowledgement in the book: “Voices of the 55th,” and had the publisher send me several copies. I’ve shared my research with a few other authors over the years. It’s a good way to get an acknowledgement in the book, and an autographed copy to boot.