Canon 580EX II vs Sigma EF610 DG SUPER (first hand experiences?)

I have a 500dg super, a 530 dg super and a 610dg super and they all work pretty well. The menus are quite hard to learn and you have to learn the trick if you want to use wireless triggers, but for the price they cost, they offer a lots of functions, manual settings, optical slave, a bounce card,and a lot more.

They're not ubild as heavily as a 580 EX II and you can't add a battery pack. The seller also told me their output is not as reliable, but I haven't had any major problem in 3-4 years. Recycle time is slower than Canon at full power.

That's pretty much it, but I'd still get 2 610dg super before I got 1 580 EX II. better value for your money in my really humble opinion.