I find Lazslo Polgar's 5334 problem book to be a huge disappointment.
It's a great concept to have problems which have as their goal, the reaching of a += or +/- positional advantage - I'm all for it.
It's just that in the answers to the problem nothing is ever explained - you are just given a variation and an evaluation. Why is this an advantage? Or why is it only slight? These are the things that matter!! And they are totally absent from the book.
Who made the eval? Is it Laszlo? Is it a computer program? Somebody else?
In addition, it doesn't say why other moves are wrong. I don't see the value for the money - but it's ok, as I got it as a present :-)
Your USCF rating is about 1400 you wrote. If we take the year 1900 as a starting point there have been 10s of thousands chess books written. Many of them aimed at learning the basics for beginners. My point is: What rating level should you be before a coach is really helpful? I believe 1500-1600. Under that you can simply use books and save your money.
I completely disagree, it's very hard to learn on your own below 1500-1600. Almost all books are hard to relate to your own games, and nobody helps you figure out what's actually going wrong.
A coach can go through each of your games with you, right after it was played, and point out what went right and what went well, and give you targeted exercises to work on the bad points to boot.