All Im in the market for a new set of paddles and pondering if I should get iambic or single lever. I currently use a vintage vibroplex single lever paddle. It's seen better days. I've used - but have never owned - iambic paddles ... the only difference I can recall is that holding down both sides of iambics generate alternating dits and dahs. As I've always used vibroplex I plan to get either their vibrokeyer single lever or the Racer series iambic keyer - is there any benefit of using iambic over single lever or does it simply come down to preference? which model would you purchase?