When choosing a 3PL logistics operator, don't just compare the price per order. Compare how they'll handle your actual orders. There are five things that decide whether the relationship works: whether it connects to your store without exporting files, whether the stock you see is the stock actually on the shelf, whether it has a clear cut-off time and sticks to it, whether it handles returns well, and whether it gives you a price you can calculate before signing.
The most reliable method is simple. Take ten real orders from your store, including the odd ones, and ask the operator to explain what happens to each one from the moment it comes in until it reaches the customer or comes back. With those answers and a cost simulation based on your own numbers, you'll know more than any sales pitch could tell you.
