Hi
I do know they are quite good as course. My humble opinion , though, is that IF you are strong in your fundamentals and have a good plan,
error log, and pinpoint exactly where you are weak I believe you can achieve a good score even without a course.
But that is me. For other people, a course is a blessing. It depends.
They have a reasonable price: the crash course is 7 days trial and then $125 which is not the end of the world for two months.
However, GC has also tons of resources, millions of questions, tools, guides, and materials for all species.
Even the GC math and verbal book is wayyyyyyyyyyyy more than enough for a 51 percentile.
It is a personal preference, frankly.
Remember that your preparation in the last stage, regardless of prep a company or not, should be the official material. There the real GMAT score comes from
I hope my humble and maybe pointless opinion helped you somehow
Best of luck Sir
Thank you for your suggestions and I would look into my weak areas and GC guides.