There is no empirical evidence that any one method of taking T is better than another. Even doing the math between the difference concentrations and dosages, I was getting the same amount of T on gel as I do now on injections. I experienced no difference in masculinization between the two. I prefer injections because I don't have to think about them everyday and I don't have to worry about exposing any of the women in my life to it like I did with gel.
For topicals you have gels and creams. There are a few different brands of this (Androgel, Testim, Axiron, Androderm, etc.). Typically if your insurance covers it, it'll be a generic or a specific brand. You can also have it made by a compounding pharmacy, though that may not offer any specific savings.
There are also pellets. These are implanted into your butt cheek and last somewhere from 3-6 months based on dosage. They are generally not available to someone who is new to testosterone or hasn't consistently taken it. The doctor you're working with will want to find a dosage that works well for you to know how many pellets to implant. My doctor will not implant them in anyone who has not been on T consistently for a year at a dose that works well for them. If you have any kind of change to your reproductive setup, that would also reset the clock. I had a hysterectomy just after my first year on T last February, and I'll need to wait until this February to discuss pellets because my dosage changed after my hysto.
I think the big difference between all of them is more related to personal preference than effectiveness.
