Our main concerns are space inside and outside.. which is why I am puzzled. We would rather the CN for space outside as two Rudds are massive, but we would also like a little leg room on the inside.
I have 3 boys in a 695, and 3 boys in a 680 (at its max). I need to intro the new boys to the ones in the 680, so they need a bigger cage as my other 3 boys do not like to give up the roomy 695 (tried this when Cas was with us, major depression from Sam/Dean/Stewart).
Cost wise, the Rudd would be free as I have two of them, but I have been dying to get the double CN and can finally do so. Worst comes to worst, I do have 2 spare cages that are suitable for 2 rats.
Also, this may end up as 2 groups of 4 and 3, not 5 and 5 if we decide to let Stewart go and we cannot adopt from MRRG. But this would be a max of 5 in each, and they get about 45 mins out-time a night. I'm always in their cage playing during the day, and random rats can be found around the house with me while I do my daily doings lol
I think we are going to go with the CN, as there is intrest in one of the Martins cages and this person could really use it.