The Arca cube is probably the most amazing piece of engineering I have ever seen.... I can't afford one... but the B1 is great if you can find one. They are in great demend. The Benro is not of the same high quality.. neither is the induro line which is a Chinese knockoff of Arca Swiss and Gitzo and of inferior quality.
I have the Accratech. It holds a V body, a winder and PME viewfinder with a 180 rock steady on a Gitzo. Not sure how much the H3D weighs. Look at the new Accratech that allows you to adjust to landscape mode easier then the original. I like mine but I might buy the Arca if I did it again. I bought the Accratech over the Arca for weight at the time which seems silly looking back. I hear good things about the Kirk, but don't know about weight tolerance issues. I just know when I cl& the Accratech down . . .it doesn't move.
I likethe Z1 Arca but it's smaller around and does not mate flush with the edge of the Gitzo Carbon 6 3 series paltform do the small pan leaver (not the large tension knob) can be hard to get to. I also like the extra weight... the Gitzo is SO light weight....
It funny the experiences one has when shooting zillions of weddings, many at a dead run, with little time to ... well ... take your time. My Arca B1 has been locked up more than once by 2 different assistants, and I have an Arca QR that simply fell apart, springs flying everywhere.
I guess Arca and I don't get along to well.
In contrast the Gitzo mag. ball head and QR used for maybe 5-6 years now has never been a problem ... and I like their slide-in QR because it accepts both Arca type plates and the Stroboframe plates used for QR on flash brackets and camera plates on my Metz potato masher.