....not to butt in, but I'm going to anyway
...I sold my HOG 23 mainly because it had a center positioned corrugated hose, which is not very compatible with a double hose regulator. However, the VDH & Oxycheq & Halcyon wings also feel like they are better made than the HOG. Additionally, the VDH and Oxycheq wings have standard/replaceable elbows and dump valve assemblies where the HOG & Halcyon wings have the 'T' nuts bonded to the bladder. One would be hard pressed to remove/repair the bonded assemblies or the bladder whereas the wings with easily removable hardware would be a snap to repair.