I was on pellet insertions for years...since 2012. just till last month in fact.
Pros: my doctor would insert me once every 3 months with pellets, test was at about 1800-1900, by third month I would be around 800-850. I liked not having to worry about injections etc. You will be sore for about 3-5 days after insertions. Labs every 3 months...
Super convenient.
Cons: expensive. If your insurance will cover it, great. I use to pay $15 copay every 3 months. My insurance changed recently so I had to adapt....
second con could be scars on your butt, they will have to make a small incision in your skin, so if you scar easy you will have to consider that....
anyways I was a big fan, now that my insurance does not cover it, I would have to pay out of pocket about $1250 every 3 months...