I'd ordered two of these magazines and received them a couple days ago.
On first examination, they appeared relatively well-constructed and the matte appearance looked decent. Compared to a Ram-Line magazine I have, the BX-25 has a little less curve to it, and looks a little better on the gun in my opinion. I don't know how it compares to other Hi-Cap mags.
The inner parts rattle a lot when empty, but as soon as a little pressure is on the spring, that stops. What is most concerning to me is the dimensions of the magazine. The part of the magazine that is actually seated within the gun is about 1/16" shorter from front to back and 1/32" shorter from side to side than my Ruger 10-round mags. Also, while the 10-round mags have sharp squared-off edges, edges on the the BX-25 are rounded and less precise. When I lock it into place, it doesn't feel as solid as I'd like. The bottom of the mag wobbles side to side way too much. My cheesy, cheap Ram-Line mag feels much more steady.
I experimented with some duct tape to see if I could snug up the fit. About 4 layers of tape on the sides of the mag and one on the front and back and the mag felt like it should have to begin with. Of course, when something is made by the same company than makes the guns, and it cost me $70 (with shipping) to get two of them, I shouldn't have to rely on duct tape.
Since Ruger's return policy only allowed unused items, I returned the magazines without ever shooting with them. I suspect they might have worked fine, but their poor fit in my gun was unacceptable to me.