I have only used sugarveil, but looked into the candy lace product. Their website says that it doesn't go yellow like sugarveil does and that it stays pliable.
Depending on what you are doing you might want it to stay pliable, or you might want it to harden like sugarveil does. Other than that, the only difference would be the price. I looked very quickly, so you may find better/different prices, but I found the candy lace to be about 40% to 100% more expensive. I believe it is from South Africa, which could be why it costs more after its imported to the USA.
Hi Leanne -
If you've mixed but not used SugarVeil for several hours, since it's naturally white, without added colorants, you just need to rebeat it to restore the natural white-white color. Here's a photo that shows SugarVeil after several hours, before rebeating (on the left), and after rebeating for a minute on the right: