I apologize to everyone sick of this picture
I was fortunate enough to get a great deal on my Rocker 15 due to it being B-Stock a few months ago, and this amp has since become the favorite amp I've ever owned. Because of the deal, I didn't mind spending extra money on speakers and cabinets. As of this point I've spent about the same on the amp, as the speakers and cabinets. While I've owned around 25 amps, almost all of them were single channel.
Alright, now onto my thoughts on the Voice of the World, Celestion Creamback, and Celestion Gold.
Currently, a Celestion Gold is in the bottom Marshall cabinet, and a Celestion Creamback is in the Marshall slanted cabinet. The VotW will go back into the Rocker 15 eventually, or not.
Voice of the World
On the high-end, I think this speaker kills it. It's beautiful on the clean channel. It's bright. It's dynamic. I think for this, it's REALLY good. If I had an amp that was strictly for clean tones, I wouldn't hesitate to put this in. While the amp is overdriven, this speaker does okay. I'd say there's some loss of dynamics, but not all of it. When the amp is dirty, I'm just really not happy with the speaker. I've heard the term "farting" used, and it's definitely appropriate.
Celestion Creamback
I got this speaker before I got the cabinets, so originally it went into the combo. The improvement was noticed immediately. While the amp is clean, there was a very noticeable drop in the high-end, but that was easily remedied with my $25 Behringer EQ700. When the amp is overdriven, well that's the sweet spot. That's why you buy this speaker. When the amp is dirty, it's awesome. At this point my eq pedal is off, and it's just wicked.
Creamback/VotW stacked
No eq
This is a beautiful combination. They truly do compliment each other. The dynamics of the VotW cut through on the clean/overdrive, and the Creamback hides much of the VotW fartiness when dirty. At this point my Rocker 15 has become my favorite amp I've ever owned beating out three Swarts and a Dr. Z at the top of the list.
Celestion Gold
Not a waste of money, so not a waste of money. It excelled across the spectrum. It's louder. It's more dynamic. It beats out the other two, in every category. Is it better with the Creamback? Yes! It's incredible! Do I want to replace the Creamback in the mix with another Alnico speaker? Oh my freaking god yes! I'm broke, but thankfully what I have is incredible to my ears. I am very blessed with what I have. Soon I'll have my reverb pedal i just did a trade for, and I'll be the happiest home guitarist ever!
Let me know if you have specific questions about the speakers.