I must deeply make a point... if you just want to play around, make small hobby projects and you are a long year user of gs - it does not make a sense to switch to the pro version of unity. It even does not make sense to come closer to the free version. It is right - the main crack is to understand a complete new thinking about developing an app. Unity is like working out a virtual set for a movie. Scene by scene. And yes - if you plan the change there will be a lot of work.

And it is not true, what some freaks here told in the past like
"It was for me no problem to switch" or crap like
"I only need two weeks".

In GS you have one single problem... to work with gs you must understand the
main key - you have to learn scripting. If you donīt learn scripting - you just can
play around with some old editors like med / wed.

When you understood gs and you reached the level "I completed a com game"
(of course - since I am a member of gs, I know, this level was reached only by the minority) you will have 3 problems with unity.

1.
You must understand a complete new developing process ( you must think like creating scenes for a movie - your work on a stage.

2.
You must understand the editor - because you work with the editor (in gs you primary work with the sed!) - and you have a very powerful tool with the unity editor to get some of the biggest needs - time. This includes the cooperation with the script editor.

3.
and you have to handle with a more difficult scripting language.

But If you are willed to do this... it is like changing from
"magix video maker" to "adobe premiere"
"med" to "cinema 4d or max"
"video fx" to "adobe after effects"

The overkill is just to work the new tool out. And for me it was a good step.
But for just play around or get some small jobs - it is not worth.
For me as a lone wolf ( paint / modle / scripting / music) it is the big food the rest of my creative life - or till the next ground breaking engine comes.

O.k. maybe you will have problems to handle the new "all with love" system.
For me as a hardcore black coffee drinker it is not possible to handle with.