My own unapologetic opinions on books and writing.
Mine is pretty easy.
5 - One of those books I enjoyed so much I didn't want to stop reading.
4 - A good book.
3 - A decently good book, but so are many others.
2 - I finished it because I promised a review, otherwise would have DNF'd it and not bothered reviewing.
1 - Unlikely to have finished it unless I got it from Netgalley. Real torture to read and I probably gave up and started skimming, or else it promised me German recipes and gave me American instant food.
For half stars, something that falls between the definitions. So 4.5 is a brilliant book but I might have deducted a point for something, 3.5 deserves better than 3 but wasn't quite good enough for 4, 2.5 kinda sucks but could be worse, 1.5 I only gave a passing thought to getting my matches out, .5, well, I burned it. Then buried it in lime. Unless it's on my Kindle, but I made a point of going on Amazon and deleting it from my cloud, lest it spread its taint.
So basically if I rate 4, 4.5 or 5, I recommend the book, at least to someone.