I've MD-ed since 1996, CRHed off and on since the 70's. I have found a higher volume of silver from CRHing, but for getting old obsolete coins MDing is the way to go. I've never CRHed a large cent, two cent piece, three cent piece, Flying Eagle cent, etc., but have found them with a detector. Also my signature picture was found MDing, an 1861-O half.
My strangest find detecting so far, was back 20 years ago in my front yard by my driveway and the road. Laying down a few inches below the surface I encountered a railroad iron piece of track. I duct a foot or two of it up and it kept going deeper, so I just covered it back up. One day I'll probably go dig it up, as long as it does not go under the road in front of my house. The railroad use to run a half mile north of me, not sure how a piece of the track ended up under my lawn.
Since this is a CRH forum my oddest CRH find was when I got a roll of half dollars from the local bank that weren't half dollars, but instead they were all large English pennies with some dating back to the 1860's if I remember correctly. I posted about it here on the forum a few years back.
Happy Hunting All.