I don't think either of them are a true mirror finish, but the SS one is very close as we ordered pre-polished material. I'll state it out here that the brass does not look like the shiny mirror that Duck has posted on his sites. As people have informed me, a true mirror finish is quite an ordeal and would cost twice or thrice the purchase price of my units. Probably thrice because of US prices. The polishing is by far the major cause of the delay as the plates only took 1 week to 2 weeks to cut per material. SS takes longer as it is harder to machine. Looking at the cost of things, for those who bought the SS, they are getting a much higher quality unit than what they paid. The brass unit people are getting what they paid for.
Personally, I still prefer the brass as it looks good in my black base. The contrast really stands out especially with my silver screws in. I'll be sure to take my keyboard apart every weekend so I can look at it.
Here's a recap of the troubles in order
1. Brass Units came in first, very shiny but very scratched. Noticeable without bright lights. I could feel the scratches.
2. Requested better finishing on the already cut SS plates. Those were scrapped and new material (pre-polished) were ordered and then cut/polished
3. Brass Plates returned, SS plates received
4. SS plates shipped to US orders who only got SS. (+1 to someone in Canada
)
5. Brass Plates received