I'm a runner firstly and generally hate doing cardio indoors, but i do enjoy a rower when i'm near one.
I'm the opposite. I love fell running but find city running totally soul destroying and fell running isn't exactly something I can fit in after work. What tipped me over was doing my achillies in a few years ago so I couldn't run at all and while I was recovering, I wanted something low impact to do. I realised I could row with less pain than running so bought myself an erg and found it perfect for evening and morning sessions in the garage! Then I got a bit addicted..
I've started back on the Pete Plan for a 3 week cycle as my prep for the BRIC