Hand cycle in gym - any good?

[Oldisthenewblack]

In my gym they have a hand bike (not sure what the official term is!) where you sit and 'pedal' your arms. I'm just wondering if anyone has used one of these and if they are good for building muscle in the arms, or as an alternative to regular cardio when your legs won't hold you up any more....

Be interested to hear from anyone who uses them.