I've switched to using Ian's knot, and have found it to be both faster to tie and easier to set up. I think once you work out how to 'pick up' the laces in the right way, so that they are already in the correct starting position, it gets a lot faster/simpler to think about.
Of course, I haven't been in your shoes - my laces are all the round type and I haven't tried it with flat ones.
To each their own!
The oval style with the sharp edges has a lot of the benefits of the flat style, but is more universally compatible. The flat ones don't always move well in round eyelets, they work better with loops in my experience.
The completely flat style doesn't tie well if one of the laces is twisted though. I think it's a great option for athletic shoes though, where you are more likely to care about a particular level of give, etc, and when you don't want your shoes to become untied. The round style is cheaper, and if you don't notice the difference it's probably a more versatile shoelace.
Plus you can do fancy knots with the round style.