Every system has pluses and minuses. SmartThings certainly has a much wider zigbee implementation. That said, the dependence on the cloud introduces a lot of instability. People move in both directions, it just depends on your own particular needs and priorities.
We should also note that the GE link bulbs have a known firmware problem that can cause them to become disconnected from the network from time to time. For this reason, they are not on the official “works with SmartThings” list, although other brands like Cree and Osram are. Many people who are otherwise very happy with SmartThings have made the decision to switch from GE links to Hue whites or other brands. So if your only reason for switching is GE bulbs, I’m not sure you’ll end up with a happy result.