I started out flying Mode 1 in 1972, had flown single channel previously for a couple of years, mentored by a great friend that's still currently and a very, very competitive Q-40 pilot. Then changed over to Mode 2 after successfully flying Mode 1, flew it around 6 months or so, and changed back to Mode 1. I discovered in racing / sport flying that I was not as smooth in Mode 2 verses Mode 1. Been a "Mode 1'er" ever since.
At this point in time, I think I am the only "Mode 1" person at our field. (we have approximately 90 members in our club)