I'm no O.S. fanboi, but I echo alan0899's opinion if I had to choose between those two. Notably the bit about good power, good transition, good idle. With O.S. .61FX you can have it all.

In the age of the "46 with the power of a 60" and "53, ..or 55 ...the power of a 60 in 46 case" advertising, it doesn't help the image that 60's are also an unfashionable capacity to own and fly right now. Plus the O.S. 61FX suffers from FX association with the woes which beleagured both its sibling .46 (peeling liner) and .91 (bubbles in remote fuel feed) plus an poor image of not being a constantly proclaimed a ".61 powerhouse" in the long since its release not interested magazine reviews or in promotional advertising as O.S. minimises focus on the ABN FX series as they are gradually superseded by the AX and ABL. Flown many examples of the .61FX and own two myself. The 61FX is particularly robust, very reliable and produces mountains more real punch than a .46 despite the implication the meagre .2ps spec. claimed peak power differential would suggest.