It's Quality and Quantity

We don't have an SL reference handy today, but Avault has a review of X: Beyond the Frontier posted. In the facts area they officially class it as very similar to Privateer 2 and make references to the variety of ships available to the player in Privateer 1 later in the article. XBTF makes you stick with the same shuttle throughout the game. You can find the review here.