Big vote for unloaded patch panels from me for several reasons.
1)If it's even remotely possibly that you could end up needing a 48 port patch panel, there's hardly any difference in cost between 24 port and 48 port unloaded patch panels. Standardize on the 48 port unloaded patch panel, and you can plan for proper cable management right from the start. Otherwise the 24 port patch panel you add later will never quite fit right with everything else.
2)If you have a wall mount rack, unloaded patch panels are the only way to go. You can't do proper cable management with a loaded patch panel if you can't get behind the rack. If you need to work on it later, or worse, terminate a few more runs, there's no contest which one is going to be easier.
3)It's not ideal, but if you really need to you can mix categories on a single patch panel. 6 position, 8 position, Cat5e, Cat6, no problem. Maybe the customer originally went with Cat5e but they insist on the 5 new drops being Cat6.
4)Someone plugged in a line cord and bent the pins? Easy to fix vs. this patch panel always has a bad port.
5)Cable management: We really shouldn't be strapping the cables in a bundle to the back on the patch panels any longer. Can't really do that with an unloaded patch panel. It forces you to at least look at doing proper cable management.
6)As you mention, sometimes you can get deals on jacks. You probably have lots of jacks in your inventory, but you don't want to carry hundreds of dollars worth of patch panels as well. Smaller investment in the unloaded patch panels means you can keep a few in the truck making you more flexible when requirements change or jobs come up out of the blue.
