They're both strangely weird. Is that a true Perpetual Calendar? If so, that would be my choice.
The perpetual is late 80's. It's original. The ones with the 2000 calander are post Sovjet. The logo on the big0 is a Sovjet quality mark. See Raketa leafelet 1989. I don't know what movement is original in the big0 the 2609N or the NANow that I pay much closer attention, I do see that the calendar is of the 80s. I once saw a model that had a calendar for 2000, I believe. I am hesitant in getting this one because of the pitting on the case back. I still dont own a Raketa and so I am afraid the corrosion will get worst.
On the Big Zero, I saw in the Raketa web page from their 1998 catalog archives an example that does have cyrillic and CCCP but no logo like the one above. That is where I am confused with the dials. I see that Big Zeros have a flat crystal and have a beveled case front along with indices markers. I am learning a little at a time.
The smaller one looked like the photo below. I do believe it was released after the larger one. I had a black dial smaller zero, and my opinion is that the larger case is the one to get. The one in your original post looks convincing to me, although the dial might be a little crooked---maybe just a camera trick.I came across a 38 mm sized big 0 that is somewhat smaller than the model I mentioned above. Did Raketa make a smaller variant in anytime in their history especially in the 90s?