A das Gupta a book I would say totally worth its price. I am currently doing algebra and trigonometry portion from it. Also friends who have genuinely solved it give credit of their strong coordinate geometry to this book. I would say if you can solve about 6-7 of 10 solved examples on your own and 8-9 of exercise problem on your own, You already have completed a chapter till advanced level. Book clearly says in preface that students should have basic understanding of all Concepts involved at intermediate level, so not at all for beginners. I would recommend it to solve only after you complete your coaching modules.
As book is based on 3T's Tips, Tricks & Techniques, so clearly on advanced side.
Difficulty rating- 8/10
Realibilty to present scenario of jee advanced - 8/10
( Considering jee 2016 maths paper)
Remember the name of book is " Problem Plus in IIT Mathematics" Are you ready for the +?