Gold does come with the mod selector- but you can get that for 1.49. It also comes with a bunch of other usermade stuff to spare people the download.
So, Online play not counting, you get:
-Drones
-Somewhat smarter AI
-patch support- important since 1.49 has the player-order problem, Gold doesn't (in 1.49 the first player in the list ALWAYS shoots first in combat. Not nice for WP defense)
-New mods like Proportions that only work on Gold
I'd say it's worth it, but then I already have it
Phoenix-D