The on/off "switch" on my outside shower head is pretty bad. It still dribbles quite a bit of water in the "off" position.
I put a Camco RV shower head (ordered from Amazon) in my inside shower. It has an on/off switch right there on the head. The flow and pattern is nice. It fits in the original shower head holder. I also replaced the hose at the same time, which I highly recommend. Probably not quite as nice as the Oxygenix (sp?), but then I paid a lot less for it too; around $15 IIRC.
ETA: Here it is on Amazon for around $11.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!