Well, many years later, but I now own both an E3 Prestige and E3A Standard. I also once owned a DC3. All are(were) silver with gold rim and cup. I sold the DC3 some time ago. At one point, I even owned a B6 baritone mouthpiece. It was sold as well.

Overall, I cannot tell the difference between the E3 and E3A. I "suspect" the difference may be some kind of royalty due Steven. I found that the E3(A) plays a bit bigger than the DC3 and have sharper rims. I think that is pretty much it.

The specs and prices are below:

Alliance E3A - Gold Rim and Cup
Cup Diameter: 26 mm
Rim: 6.78 mm
Bore: 7.4 mm
Cup: Standard
Comparison: Denis Wick Classic SM4 and Ultra SM4U, Bach 4G, Schilke 52D
88.30 (excl VAT)

Alliance E3 Prestige - Gold Rim and Cup
Cup Diameter: 26 mm
Rim: 6.78 mm
Bore: 7.4 mm
Cup: Deep
Comparison: Denis Wick Classic SM4 and Ultra SM4U, Bach 4G, Schilke 52D
100.32 (excl VAT)

Alliance David Childs DC3 - Gold Rim and Cup
Cup Diameter: 26 mm
Rim: 6.73 mm
Bore: 7.45 mm
Cup: Deep
Comparison: Denis Wick Classic 4AL and Ultra SM4U, Bach 4G
119.23 (excl VAT)