I think the C++ language be the most used recognised people using today. I not know much coding so not knowing which one is the best, but most of them are made in c++ mode I think.
For asi, you need asi loader, which can get detected for online, and cause bans. So better to be DLL or EXE and inject direct to the gta5.exe
I think the visual studio 2013 is the better one, 2015 not work as well for me.
You could download one of the SOURCE CODE here from mpgh and see an idea of how things work.