There are positives and negatives with regard to both styles of cages, and every mouse owner you speak to probably has a different opinion on which is "best".

The problem with many cages manufactured for gerbils and hamsters is that often the bars are spaced too far apart – allowing young or even adult mice to escape – never underestimate the space your mouse could fit through! Another possible negative about cages is they often have a plastic base with exposed edges that mice can reach and chew at until there is a hole big enough to escape. However, cages are very well ventilated and with mice and rats this is important since they can smell if not kept fastidiously clean.

Glass tanks will not allow your mouse to escape if there is a secure lid, but the air does not circulate as well. This is not a problem if you have a high standard of cleanliness, and in particular you could clean the area they use to urinate in every day to maintain a low ammonia smell. That said, glass tanks are also a lot easier to keep completely sanitary, for example you can perform a once-a-month disinfection by filling the tank with soapy water and scrubbing. This is not so easy with cages.