Regarding sound, there is a reason why some synths cost $$$ and others are free. I don't know any freeware at the level of Sylenth, Hive, etc. Some have similar features, but the sound is not the same.
Noizefield also seems to loosely emulate Sylenth:
http://www.noizefield.com/products/4-tune
They have several similar synths...
Then again, when you don't have money, do you even have a powerful computer and good audio equipment to hear the difference?


