The smaller the server is, the higher the prices are and the more markup crafters can charge (thus, more easily earned housing). PvP is done via duty finder and so the particular world doesn't matter.

The main reason to pick a larger server is social scenes outside of instanced content. If you don't particularly care about that (and the cross world PF gives less reason to), then your crafter friend would probably prefer the smaller world where markups are more generous and gil can be earned easily.