Reddit reviews Concordia: The Lutheran Confessions -- A Reader's Edition of the Book of Concord

Like others, I'm not completely sure what you want. Could you list the confessions you want? For what it is worth, I don't think the subreddit affirms specific confessions - it just lists some common Reformed confessions, some of which contradict each other. It does affirm some modern statements, but that's a separate discussion.

I think you should find everything you are looking for and then some (including Baptisty stuff) in the third volume of Schaff's Creeds of Christendom. You'll even get both the original languages and English translations. It is a three-volume set, but all of the Reformation creeds are in the third volume. You should keep the first two though - volume one has all of Schaff's commentary/analysis and volume 2 is the Greek and Latin Creeds. If you don't need a physical copy you can get a free e-book from CCEL.

Personally, I don't think a single-volume collection is that useful. There's no harm in having things split over multiple volumes. Here's my hard copy collection:

• Our Faith: Ecumenical Creeds, Reformed Confessions, and Other Resources - this covers the Apostles' Nicene, and Athanasian Creeds, Three Forms of Unity, The Belhar Confession, as well as the amazing Contemporary Testimony Our World Belongs to God.
  
• Book of Confessions - this covers all of the Presby Stuff - Westminster and Scots as well as the Second Helvetic Confession and an extra copy of the Creeds and the Heidelberg. You get the Declaration of Barmen and some other modern stuff as well. My version doesn't have the Belhar, but the one I linked does.
  
• Book of Concord - all the Lutheran confessions you will ever want. I also have a pocket-sized copy of Luther's Small Catechism because the big book is just too big.
  
• The Book of Common Prayer - includes the 39 Articles of Religion, among other things.
  
  A big benefit to my approach I think is that I get the modern translation of all of the confessions, which I see as a big benefit.

Book of Concord.

And, because it's an awesome resource to be available, bookofconcord.org.

Here is the mobile version of your link

I was hoping to find, essentially, those two books in one hardbound volume. But that is the content I'm looking for. I already had this version of the Book of Concord on my list.

Edit - Actually, given my general distrust of anything officially PC(USA) I might go for this instead.