My opinion
The best if VCDS, Second and for most people the best is OBD11, Third is Carista.
Carista is good and also supports non VAG Models but its a button push service so you can not code your own changes you need Carista team to build it. Also carista you have to pay if you want to keep modding.
OBD11 Is Android only at this time but the IOS Version will be fully functional by the end of this year and will also be supporting BMW later this year / next year. There are some apps but this tool is designed for the user to make the changes but gives you access to much more.
So if you just want to make a few small changes Carista if you intend to do more then OBD11.