Either brand will be fine. Like most things when it comes to brands, it often comes down what someone is used to. I'm familiar with both brands and have not found one to have more or less issues than the other. The Good brand is step up in quality, if you wanted to look there. But nothing wrong with L or M.
8-plait is not really needed for either windlass if the rope is in good shape - I've used/seen/familiar with 3-strand being used much more often. The reason that 8-plait helps is that, quite frankly, Grady doesn't build the anchor locker deep enough. In this case, the 8-plait lays down better so it works in a shallower locker. Other boats, with deeper lockers, 3-strand is just fine.