You'll read "deeper" books, but few as consistently challenging. Chambers speaks, in one-a-day bites, about the devotion a Christian must have to be obedient to God. These aren't "sound bites," but morsels of a very meaty meal. Catholics and Protestants both will find Chambers pointing the way to Heaven, and helping us know how to live out Christ's plan while still on Earth.
A verse accompanies each day, and these ought be looked up to see the fully context. Have your Bible and a notepad next to you.
Chambers is candid to say the Christian life is difficult, but encourages us that this difficulty should challenge us, not scare us away. Maybe Chambers might like the slogan "A few good men," except this time referring to future converts?
For people who like the "Daily Bread" booklets, check "My Utmost" out. Like the DB series, each entry will take you just a few minutes to read, but plenty of time to ponder.
Use this together as a discussion step with another person, your spouse or small group. Figure out why Chambers places the standard so high -- does Scripture agree? And once you figure out the answer for a given day's passage, now what? What is your response?
I read an entry and realize I've got a long way to go, but feel glad I'm on the road.