I purchased 4 of these to try out, and I'm not impressed. It looks like they were trying to offset the center tube hole so that you could more easily drip down the middle to refresh your carto(although that may just be an inconsistency in production).
They hold a lot of juice, but the couple I've tried all have a real funny taste to them. From what I've read, the vendor is saying that is because there isn't enough juice in them. I've filled these things to the brim, and all I've ended up with was wasted juice and a silly taste. I think I'll stick with my BOGE soft tips.