Laces are the easiest to replace and if you are really finicky about your fit, they fine tune the most. They also stretch, loosen, and the boot softens up. I find having to re tie my boots when I am out a bit of a pita.
BOA laces don't really stretch, but the boot still softens up or pack out from the pressure of the laces so to speak. The tighten them up, isn't even 1/10 of the chore it is for regular laces. Spin and go. You can over tighten BOA cables fairly easily though. They are a bit more time consuming to replace, but it is fairly easy. Takes me about 15 minutes for a pair of boots. You'll have the have the replace cable and tool to do it. Something you can do in a cafeteria. If you are in the field, like the backcountry, you are probably not going to pull this one off. A long Voile Strap around the boot works pretty well. I use the double BOA system, and the only cables I have had bust are the uppers. This has happened after pluse 60-70 days on the boots, so overall I am finding BOA reliable. For what I do, it's way more ideal then laces.