Duplication (CD-R) or replication (silver CD)?
It depends on how many you're looking to have pressed. It used to be that CD-Rs were the only option if you wanted fewer than 1,000 copies, but that number has started to drop in the last couple years. Here's a place that will do replication for orders of as few as 500 pieces, and the price seems okay for their eco-wallet package:
CD Replication In Eco Wallets | CD Replication Services - EasyDisc.net
With both duplication and replication, obviously the price per unit goes down the more that you order.
If you're looking to sell through CD Baby, they don't give a shit whether it's silver or CD-R. Guitar Nine will only sell silver CDs. I don't know about The Laser's Edge.
Reviewers are also a question. Most music mags & such get zillions of review requests these days, and a professionally packaged silver CD is probably going to be more likely to garner a review. I'm not sure how much difference this makes anymore, when a well-done YouTube video probably garners more hits than a guitar mag review would.
I did duplication on the two albums I've had pressed, since I knew only a few freakazoids would likely be interested, and I didn't want to have to deal with storing a ton of CDs. Professionally duplicated CD-Rs don't look like the blank ones you get at Best-Buy. Frankly, you have to look fairly close to even tell that they're CD-Rs, since the color of the coating is closer to silver than to blue.