Robo's are too small and too fast for little fingers. They are shy, fast, skitty and wriggly. I've had two (sisters) for six months and one is lovely and responds well to handling; but the other is vampire hamster and will make a detour to take a chunk out of you.
Syrians are ideal for little fingers, as long as you choose well. Take at least a week to choose; go and visit them at the pet store at various times; and insist on handling them.
We did this and had a "shortlist" at two different pet stores; third visit; pretty hamster took a chunk out of both husband and myself.
We went back To "ugly" hamster; who I'd rejected on the basis of ugliness on our first visit; but she chose us. She was just so affable and lovely.
She died yesterday and I am overwhelmed with sadness at the moment.
Rotostak cages are bad news.They look fantastic, but they are insecure and not really for the hamsters' benefit.
I bought two; the space station; and another big unit (can't remember the name now). I bought "ladders" for the Robo's.
They're insecure, difficult to clean, in practical... humans buy them, but hamsters wouldn't choose them.
I ended up buying two Ruffy cages (3ftx2ft)with stands; they have what I consider to be reasonable space for two Robo's and one Syrian respectively. In addition, because they are so deep, you can bury tubes/burrows in the shavings etc. I also had/have bridges/burrowing towers. This mimics their natural environment; is secure and hygienic.
Having said that; my Syrian died yesterday, very traumatically.
To say i am sad is an understatement.
And no; I won't be getting another hamster