Yeah, Robos take a fair deal of taming and shouldn't be kept in a habitrail as the round design can actually make rodents insane. I'm sorry you had a bad experience.

As a rule, you should allow a new pet of any kind to settle in and not handle for the first week or better. Hamsters will be extremely flighty and nippy when you first bring them home, even when they are really sweet in the pet shop. They will calm down a little every day, but it does take baby steps to get them used to you. My new hybrid, who I've had for a week now, totally freaked out when I first tried to handle her a few days ago and dove out of my hand and landed head first on top of her wheel. I was really worried that she was hurt. Thankfully, she's fine, and we've had to slow things down even more. I know she'll be a sweet girl as soon as she chills out.

"Russians", AKA Campbell's dwarf hamsters, do need to be bred for temperament or you will get little bastards who just like to bite. I've had two like that. It's also a little-known fact that the damn pet stores should put in every cage... Campbell's tend to be territorial and cage-aggressive, so if you stick your hand into their space it's more common for them to bite than to not. Territorial Campbell's can be taken out of their cage with a cup, ladle, or even a gloved hand, and they are usually very sweet once out of their cage.

And another good factoid: My Robos eat, drink, pee, and poop just as much as any of my Campbell's, and they eat, drink and poop just as much as my Syrian (though the poo pellets are smaller, of course). The two I have also seem to get their cage smelly faster than my Campbell's, I guess because their urine is even more concentrated. Robos have a faster metabolic rate than Campbell's, and they both have a faster metabolic rate than Syrians.