Sorry, another Habitrail hater checking in. It's small unless you spend an absolute mint (and even if you do, it's still not ideal), time-consuming and fiddly to clean, bad ventilation, potential for condensation or even mould build-up, difficult for taming nervous hammies, circular (hamsters like wall-hugging, it makes them feel safe), not large enough for a big wheel, compartment design can cause fighting in groups, Syrians can outgrow the tubes, and dwarf hamsters' soft furry feet struggle to climb them (unless the setup is all one level, as with Jasmine's old setup, rather than the vertical design they normally show on their boxes).
They're made to please people, not hamsters. Just completely unsuitable.
