Well, you're talking apples and oranges. The RCM is a solid state while the Andros is a tube preamp so I'm not sure how meaningful any comparison would be outside of your system. Is the rest of your system tubes or ss? What cartridge will you be using?
I happen to own the new version of the RCM (the Furutech version) and in my otherwise all tube system the RCM sounds very clean, very transparent, neutral, and dynamic. But you already know that since you're familiar with this product.
The Andros is also quite a bit more expensive so you need to take that into consideration as well unless it's not a factor. From what I've heard about the Andros, it sounds like you can't go wrong with either unit, all else being equal.
I happen to own the new version of the RCM (the Furutech version) and in my otherwise all tube system the RCM sounds very clean, very transparent, neutral, and dynamic. But you already know that since you're familiar with this product.
The Andros is also quite a bit more expensive so you need to take that into consideration as well unless it's not a factor. From what I've heard about the Andros, it sounds like you can't go wrong with either unit, all else being equal.