transdermal aka shot/sublingual/patch/creme, benfits are strong estrogen absorption and quicker body response to estrogen dependent growth.
oral/pill, benifits are low cost, downside, the liver breaks the estrogen down into a lesser form of estrodial. but the benifit is a bi product called Sex hormone binding globulants, that bind the free floating testosterone in your system. thus working like a slow paced T blocker.
I was on low dose pills for about 5 months now without knowing the real reason why, and my endo told me after demanding to know why, and it was so my T levels would slowly drop due to the SHBG without the need for adding T blockers to the mix, so my liver/body didnt have the extra chemicals processing through it. then he put me on a high dose Patch along with my old doses on the pill. each endo does it diffrently. but their is reason for it, and in the end it all usually works out, just depends on if you wanna take the slow/safe/and cheap way, or what my endo calls Shock HRT, which involves T blockers and high E right away.
I prefer the patches and the pills, cause it keeps your mental state/mood fairly evened out, one of my friends who used the shot was on what I call a rollercoaster from hell. her benifit is she looks alot more feminine then me already. tho, she paid for it with insane mood swings.