We have the Snuza Go. I think the only difference is the Hero will vibrate to try to wake the baby if there's no movement after so many seconds. The Go doesn't have this feature, but I didn't feel I needed it. I would be racing to his crib the second the alarm went off anyways!
We love our Snuza! I use it now, even though baby is right next to us in the pack n play. It's been nice to have since he started sleeping long stretches since I'm not waking up every few hours anymore to check on him, and when I do glance over, it's so much easier to see the light blinking than trying to see if his chest is moving up and down.
We have the snuza hero and love it! Like pp said the only difference to my knowledge is the vibration. It doesn't alarm you until after its attempted the vibration. And if the baby responds to the vibration it just continues to monitor. If it has to vibrate 3 times in one minute it sets off a different kind of alarm to let you know baby is breathing but something is wrong.
Re: Snuza Go vs. Snuza Hero
We love our Snuza! I use it now, even though baby is right next to us in the pack n play. It's been nice to have since he started sleeping long stretches since I'm not waking up every few hours anymore to check on him, and when I do glance over, it's so much easier to see the light blinking than trying to see if his chest is moving up and down.