there is always a lot of debate over these topics, but I think it all comes down to the individual experience. The key is being happy with whatever method you choose from what is available to you.
For me it would be pellets > patches > injections > pills
general take on pros/cons from my own standpoint (can you guess which one I'm using?

) disclaimer: I am not a doctor and not pretending to be one... take this worth a grain of salt
Pellets
+ steady dose release over 3-6 months
+ no peaks/valleys
+ no daily routine
+ cheap on low dose
+ more effective, quicker feminization (as a product of steady release, no valleys)
+ easy on liver
+ very stable mental state (as a product of steady release)
+ very easy on the body (closest possible thing to actual ovaries)
+ no side effects
+ easy to forget about being on HRT
- must be surgically implanted in office by a doctor
- more expensive when starting out (but faster feminization)
- cannot "cancel" a dose
- must keep bandage dry for first 3 days after treatment
Patches
+ easy on liver
+ can be applied at home
+ fast feminization
- can fall off
- can cause rash/allergy to adhesive
- peaks & valleys
Injections
+ easy on liver
+ can be applied at home
+ fast feminization
- involves needles on a weekly basis
- severe peaks & valleys
- possible mental effects due to hormone surges
- testosterone can rebound during valley (impedes feminization)
Orals
+ cheap
+ easy to administer
- slowest feminization
- bad for liver
- bad for mental state
- daily peaks & valleys
- daily routine