Injections gave me -much- better results and feminization compared to pills. I was on an ordinary regular dose of oral estradiol, but once I started the injections, I got so much breast pain, and so much development. It's crazy. I feel way better, too, and it's so much easier to inject once a week or every two weeks, than to take all those pills (or pill halves) sublingually every day.
My advice - do it. Try it out. Get your doc to switch you over. It's so much better, at least in my opinion. Plus there's less risk of liver damage and all that.
Edit: I'm going to add, I was Tanner I, pre-injections, at like 1.5 months HRT. Now I'm at Tanner IV, at just over 4.25 months HRT. Your milage may vary, of course. Genes and other things play a factor. My family has big boobs for sure - my cousin even got breast reduction surgery.