SFG may help you clear prelims, but it is a flawed program. This will be just my opinion; feel free to discard it.
SFG targets are unrealistic. They may be attainable, but they come at the cost of physical and mental fatigue in the long run. And with no time to self reflect, due to it being a six-day program, the locus of control falls out of the hand of the aspirant.
Many people joined SFG Level 1 to help them cover the syllabus, and many freshers must have entered it too. But the targets do not reflect this. To give an example: asking someone to cover the entire Indian Art NCERT in a day for one who has not read it before will lead to more harm than good. Frankly, the targets appear poorly thought out in general.
What happens is that as Prelims approaches, SFG has drained all the energy out of them. However, if they indeed followed SFG rigorously, they may clear Prelims. But their energy after Prelims will be below par. It will take the person, days if not weeks, to get out of the Prelims rut. The primary battleground that is Mains will suffer due to this.
On a side note, the SFG is made to look like a selective program with SFG and RLG lists, but people who attempted 0 questions in the entrance test were allocated RLG. Why take an entrance test then?
Also, we recently received a mailer to join a program on Essay and Ethics and how this is the best time to prepare for it. But, I remember reading a blog, 'Is it too early to join SFG?', when the SFG was supposed to start on 15 Dec, which said that one should dedicate all the time in the world to Prelims, essentially scaring any rational being to join the program.
SFG may be good, but it is not the panacea it is made out to be. Berating students who are unable to keep up as not trying hard enough is uncalled for. This exam requires self-discipline and self-introspection. Develop these through whatever means. Clearing prelims is essential for mains and interview, but SFG is not the only way.