I always see questions on print-on-demand services, especially concerning Amazon's CreateSpace, so here's my thoughts!
I've printed all of my books with CreateSpace. Here's my most recent one:
Not a perfect picture, but you can see how colors look on their pages
This book is 220 pages, full color, and costs me $16.25 to print. My previous book is 102 pages and costs $7.99 each, also full color.
The quality is probably as good as you'll get with print on demand. Not to say that's it's the best, but you can only get so much quality out of this kind of service. The covers are really nice and glossy and the paper is a good thickness. It doesn't feel flimsy and cheap at all.
Anyway, I chose CreateSpace for my first book at the time (years and years ago) mostly because it was cheapest. The only real alternative at the time was LuLu. CreateSpace also automatically puts your book for sale on Amazon, which is pretty neat. I've never had any problems with their service. PDF approval times can take as long as 24 hours, but I've found that they've become much quicker in recent years. Shipping times are good and I've never had any issues with the 100 or so books I've ordered from them.
As for e-books, I've republished my first book as an e-book but I'm not an expert on it. You push the "Publish this book of Kindle" button and that's it! I don't think I even had to make any changes to the PDF. It links up with a separate service called "Kindle Direct Publishing." I've only sold, like, one e-book and I don't have a Kindle myself, so I can't really say anything more about it.
Here's what they're store front
looks like, and here's a little video
showing my CreateSpace books.
Hope this helped!