Which is better, reading The Trollogy or the Separate Books?

There are three Smelly Troll chapter books to read. But should you buy them separately or purchase The First Trollogy? The First Trollogy is books 1-3 in one big, snotacular volume.

The Smelly troll paperbacks so far

The First Trollogy contains full length chapter books The Troll Trap, Mr Splendiferous and the Troublesome Trolls and Trolls On Ice. Gourmet Girl Burger is a separate short story.

Let's be honest here - the trollogy is a massive book. It is stuffed full of trolls. It will take you a...