My friend and I went in on a Revision F rackmount, lets say I found it dirt cheap and in order not to sell it I asked my friend to go half so he could stop my insanity of selling it later on. I have owned a Rev F rackmount once before and kicked myself in the ass for selling it....
I have also owned DR R0005 (Rev C) which basically sounded even closer to a slo then the Rev F. I also owned R0394 or somewhere around that S/N which was a Rev D but Rev F is my favorite, and yes orange Channel is oh my god good....
Breakdown of what I have owned in the early 2 channel rectos
Rev C very bright and as close to a slo as you can get
Rev D Darker then any of the other 2 channel rectos I have owned, not sure if it was just mine or they are all like that. Also close to a slo
Rev F is a nice mix between the Rev C and Rev G
I have owned many 2 channel rectos, including about 4 rackmount Rev G's, all the Rev G's I owned where very consistant in tone, I never really heard a difference between the rackmount version and the head version like some people claim and I have done side by side comparison.