My dad used to be a roller coaster operator (when he was a teen), and he says that wooden ones can be rougher on you (b/c wood rots and stuff); in comparison metal doesnt rot, and they can put anti-rust on it. just my 2₵
Not exactly the case. Wooden coasters can actually outlast a steel coaster if it's properly maintained. Unfortunately, at least in the US, the problem is that most parks don't care enough to maintain the wooden coasters. There are shining examples of what a wooden coaster should be like (Phoenix at Knoebels, Mystic Timbers at Kings Island, any of the woodies at Holiday World or Kennywood) but they are the exception to the rule sadly.
The biggest thing is that wooden coasters are fairly easily to replace wood on while replacing steel can be more complicated.