Regarding the skybell, One of the employees said just this week that they are getting close to unofficial SmartThings integration, but it’s not released yet.
Meanwhile, since both SmartThings and skybell have an IFTTT channel, you can get indirect integration that way. If you’re not currently using IFTTT, you want to check to see how much lag you get. At my house we get a pretty reliable eight second lag for most IFTTT requests. But people who live in other parts of the country have reported lag of as much as two minutes when a recipe fires.
In addition, you can be a polling delay of up to 15 minutes to fire a recipe if it’s based on a switch or sensor reporting.
So it just comes down to your own use case as far as whether the IFTTT method will work for you or not.