Whether it is 'any good in a fight' will depend on the way they train, their core techniques, the emphasis they give to self defence and the competence of the instructor. Goshin jitsu is normally quite pressure point heavy and so can be brutally effective or fairly ropey depending on the susceptibility of the person you are doing it on.
The other thing to decide is what you mean by fight - do you mean a guy having a crack in a pub or the cage? If the former then I personally have some concerns about UFC type stuff, but if the former then it is likely to be ropey for cage stuff, perhaps less so for a chap in a pub.
Postatem obscuri lateris nescitis!
Martial arts, self defence and jiu jitsu in Bedford and Huntingdon - www.jitsu.me