[mafribe]

   book that's more popular 

Yet another benefit of popular books is that they won't be first edition, so a lot of mistakes that make it into the first edition will have been ironed out.

Don't underestimate how much a strategically placed typo can confuse a learner.

Rule of thumb: avoid first edition maths books.

[_asummers]

I once had an analysis book that began the chapter "There exists epsilon < 0", which I found very amusing.