Singhania is one of the most authoritative books on Taxation. When I started my PE-2 a lot of people had suggested me to go for T.N. Manhoharan as it was more lucid and more exam oriented. But i learnt from my Audit Manager that even though Singhania may be a bit complex in terms of how it approaches the subject, once you get used to it, you will be able to grasp many of the concepts in its essence rather than trying to cram it simply.
Please understand that the CA exam is very dynamic and you will be deceiving yourself if you were to think that the same old routine questions will come. True enough I performed well in my Tax exams and I was very comfortable with the subject all because of Singhania. Start with it and you will never regret it. There may be times when you feel like putting it down thinking its too advanced but thats what ICAI wants it to be. Thats what they expect you to have also (Expert Knowledge!)
So Singhania it is, in response to your question. Everything else is miles away. Hope this helps.