If you have been developing games in GameMaker Studio or follow the trends in game development software you will no doubt have heard that YoYo Games have released GameMaker 2. The big question is should you upgrade.
The first thing that comes to my attention is that many of the development kits and other coded assets in the marketplace have not been updated to work with GMS2 including some official YoYo Games assets. If you are an artist or have limited programming experience and want to use the example projects or development kits to kickstart your project then you will find yourself at a loss with GSM 2 compared to GMS1 at this time.
The user interface has changed in a big way. I find that the new GSM 2 took time to get familiar with but have begun a project in GSM2 Ia getting the hang of it. I can not say which is better because that is for you to decide for yourself but if you are moving from GMS 1 to GMS 2 then you will need to spend some time becoming familiar with the new interface. The way you edit and create sprites and sprite animations have changed slightly and so has the way you add and edit events. The workspace is also layout in a way that feels like you are working on a large canvas, unlike GMS1 which often requires you to have a lot of windows open.
GMS1 has been the development tool of choice for many developers over the last few years and has a large following which will make it harder for people to want to move so the question is should you move of stay.
In my opinion, GameMaker Studio 2 offers a lot more potential moving into the future and will eventually be as supported widely by asset developers and the GameMaker community as GSM1 is supported currently. I would recommend starting new projects with GSM2 unless there is a very specific reason why you must use the older version GMS1.