i have a zoom h2 , the line in records less noisey then the mic in , the only down side to using the line in to record with is you cant control the recording level , the way i got around that problem is to get a inline volume control device , i picked one up at radio shack for about 5 bucks , you put this on after the battery box and before the recorder.
on a side note , my inline jack went out on my recorder also , one of the channels went out , so
i upgraded to a edirol r-09 hr , and becouse of that ive got a whole new can of worms to deal with ,
go figure ?