Out of those, the R84 is my choice. It just sounds great and vibey on anything.... guitars, drum overheads, drum rooms, crotch mic, horns, etc...

M160 is a little bit different of a ribbon... its not figure of 8 pattern like most. I believe it's hyper cardiod. Nice on drums and guitar cabs... little more focused and less "big" than other ribbons.

R121- Vanilla, IMO. Sounds nice, but a little boring. Never my first choice except for chuggy metal guitars.