I am only familiar with the process for US citizens...
A German Supreme Court decision last May opened citizenship restoration to many more people. One of my friends, who had applied years earlier, was able to readily complete the process after that decision. I've submitted all the paperwork for myself and my son, and am now waiting to get an appointment at the local consulate.
The United States website/UI is not the greatest, but I found a helpful intern at my consulate, plus the fact that my mother can read/write German enabled me to understand what they wanted.
Advantages: German citizenship gives you access to the EU, helpful if you're thinking of living/working there for a period of time. If you are a resident, you will have to pay those taxes, and of course the US always wants its cut. The arm of the IRS is long.
JoAnne Goldberg - Menlo Park, California; GEDmatch M131535
BLOCH, SEGAL, FRIDMAN, KAMINSKY, PLOTNIK/KIN -- LIthuania
GOLDSCHMIDT, HAMMERSCHLAG,HEILBRUNN, REIS(S), EDELMUTH, ROTHSCHILD, SPEI(Y)ER -- Hesse, Germany
COHEN, KAMP, HARFF, FLECK, FRÖHLICH, HAUSMANN, DANIEL -- Rhineland, Germany