I have elastic speed-laces and I love them.

It was much easier to be able to open my shoes wide up in the transition area so that coming out of the water I could slide my foot right in and pull the tab to tighten them.

To me the elastic is nice because if I accidently tighten the tab to far down the elastic has a little give so I'm able to keep going without adjusting it.

I can't tell you how many times I had to stop during running races to tie my shoes. If only I had found these before I started doing triathlons. Now I just leave them on my shoes for good.