I wanted a large light source so I decided on the 150cm Pro version from Walimex, mainly because it's cheap and comes with a grid.
Quality is ok for the studio where it'll remain setup and not taken down, but the speed ring is a cheap piece of crap. I'll Octa is also very heavy, and puts the structural integrity of my BxRi flash body at the limit. Care should also be take when mounting the Walimex, it's pretty heavy and it bent the mounting ring of my BxRi unit out of shape.
Lighting: Elinchrom BxRi 250 shot into a Walimex 150cm Octabox with grid. Triggered (naturally) with Skyports (build in).