The Bar spacing is Perfect for Ratties, even baby ones. The assembly was pretty straightforward. We had one bolt hole that was mis threaded/ cross threaded so that was frustrating and it will probably never come back apart. It was better quality than expected. I was worried when ordering that the litter pan that slides out would be problematic leading to escapes, but after a week we have had no issues, and we have an escape artist in the mix. The Ramps were frustrating and never seemed to work right, we ended up using shelves from their old cage for the ramps instead. If you have ratties that chew through everything, the plastic shelves may not hold up well over time. 

Much better quality habitat than those we have gotten from the pet stores, Lots of room, no wire floors and nice large doors for easy access.  I would buy this again, and have recommended it to a friend already.