The only time I had an injection in my doctor's office was the first time, and I did it myself. My doctor wanted to teach me how to do self injections and he monitored my first shot.
After switching back and forth between injections and orals for over ten years, I have no doubt that, for me and my partner, at least, injections are far more effective than orals. But now the serum seems to be in short supply.
Another thing I have found is that it is hard to find a doctor willing to prescribe injections. For ten years I had one doctor who was amazing in both his knowledge of treating transwomen and his methods in doing so. Now that I've moved out of state and my old doctor has retired, I am finding most doctors cannot break themselves of the mindset that transwomen should be treated like natal women. They cannot seem to fathom we are not the same in physiology. I am working on that...