Are ready-made protein shakes worth the extra cost?

Ready-made protein shakes are certainly convenient. You can keep one in the fridge, take it to work or drink it immediately after training without having to mix anything.

The downside is the price. They can cost considerably more per serving than buying a tub of whey and making your own shake.

Do you think the convenience and taste make ready-made shakes worth paying extra for?

Do you buy them regularly, only when travelling or caught without food, or avoid them completely? If you make your own, have you found a protein powder and milk combination that tastes as good as the bottled versions?

I would also be interested to know whether anyone compares the cost per 20 or 25 grams of protein before buying, or whether taste and convenience matter more.