I don't have a lot of experience with this rack. But, from chatting with a few friends that have the Jannd extreme front rack this one appears to be pretty much the same, for less $. It's from Soma fabrications, which is very reputable. The only problems I've heard of is if you don't have all the braze ons for this type of rack it can be a huge pain to mount.
I've been looking at the Lhasa for my touring set up as well. I think having the added ability to strap something on the top of the rack would be nice (an ability I don't currently have). I haven't really put more than 25 lbs on front rack - ever. I try to distribute weight evenly across the wheelbase.
In terms of the Surly, I think it's expensive, and I doubt I would every put 70lbs on the front of my bike.