Please note that I am refering in my post to Unity Indie version (the free one)..

Without going to much in technical details, I must say that with unity if you want custom shaders or some special effects you will need the pro version...and that means more than 1000 USD spent...while with 199 USD (I use Euros, but I think in USD is somewhere near this), you can have A7 commercial that already include all this features.

If we go a litle deeper just take a look at Unity API and A7 API and the way to use it, lets say in vector calculation..Its much easier to work with A7 and Lite C that with Unity and C#.

Now try to explore unity in vector operations....code a little and put some pressure in the engine...do some experiments and compare the speed of execution...you may find something interesting.

Yes..you can create your own stuff in C#, and improve the speed...but if we use an engine, is precisely to avoid having to code from scratch a bunch of things that (otherwise we could write our own engine).

I like to have an idea...implementing it and follow ahead to the next one...with A7 commercial I can do that...With Unity free...I have to stop..and say..OK I will add this little feature when I buy the pro version..so my final product will be inferior unless I spent the full amount.

Last but not least...you really need to learn C# if you want to use Unity...While C# is not a nightmare, it has a higher learning curve to become confortable with than Lite C, so a beginner can start to produce some interesting results sooner with A7 that with Unity.

Unity is very good...but with the indie version you will get a good learning tool for your complex projects (nothing wrong with that)...but you will have to move to pro version when you start to go deep into those projects..or they will lack the quality you have in your head.

I dont know if anyone has understood what I said (I am doing 3 things at the same time !!).

Best

Martins