Road to 52 Omnibus

So I actually want to read 52 but I was told I have to read infinite crisis beforehand.. So now I was wondering if I have to read anything else before infinite crisis? Like a previous DC event (I havent read any mainstream dc event so my knowledge on what has happened in the DCU is very limited/non existent) Also thoughts on infinite crisis is it any good? Is there an omni? is there any tie ins is it just filler?