I don't know if it makes sense to compare fixed ratio and fixed fractional in an absolute sense, ie this technique is always better than that etc...i think they're just different, like apples and oranges. You could take your backtest pnl or better yet, your actual pnl, for a certain period of time and compare no money management with fixed fractional and then with fixed ratio and see which would have done better for you for your particular system or trading style for that particular period of time, then base your decisions on that....i think the results will be different for different people depending on the behavior of your performance or your strategies' performance. You can take any MM technique and play around with the parameters to make it more comfortable for you to trade with that MM technique.