So celestion claims the gold has increased power handling without affecting the tone. Has anyone heard the gold back to back with a blue? Do they really sound the same? I'm thinking about picking one up... I've got a Traynor YCV50 with a vintage 30 now, and I'm curious to A/B that with the gold.

I may be building an amp in the near future, and I'm trying to decide if the alnico's are really worth the extra $300 or so over a V30 or something else reasonably priced...

Well, there's no really good way of telling, since you're usually pushing the blue really hard but not the gold with the same amp.
That said, I liked the Weber Blue dog better than the Gold. They're cheaper and have more options available. I do think the ceramic Silver bell would be better for your amp though. More bass response.
Yeah I realize that it's not an easy question to answer... I mean no one has objective data for selecting any speaker, I was just hoping to get a little closer than a shot in the dark.

The real reason I'm curious isn't for the Traynor, but for an upcoming build of a Dumble Overdrive Special clone. I'd build a 2x12 cab and I was trying to choose a speaker.

Well you wouldn't want to use a Gold in the same amp you'd use a Blue because these speakers work best near their maximum wattage. For example, a pair of Golds in an AC30 would be pushed A LOT less then two Blues so the tone wouldn't be as good.
Since you want to put a 50w Gold into a 50w amp, I think it would sound great. I have no doubt that a Vintage 30 and an Alnico Gold would both sound really good in that amp, it's just a matter of tone preference. The main difference would be the Ceramic magnet vs. the Alnico magnet. IMO, I think you should buy it because you can always change back and forth as your tastes change. Also, you can always buy one at a store that has a descent return policy if you decide to take it back. Your quest for better tone shouldn't be hampered by cost. You might also want to do more research on the tonal differences of Alnico and Ceramic magnets. Here is a site with some sound clips: http://www.proguitar.de/AudioDemo/CompareSpeaker/CompareSpeaker.html
To get better opinions , you should describe the tones you are looking for as well.
Well you wouldn't want to use a Gold in the same amp you'd use a Blue because these speakers work best near their maximum wattage.

While your comment makes sense, Gutch, I don't know that it is truly accurate.

The Dr Z, Ken Fischer designed, Z Wreck which Brad Paisley uses and has the most incredible tone I've ever heard; comes in only one configuration. Head / 2x12 open back cabinet.
And what's the cabinet loaded with... 1-Blue and 1-Gold.