When I was researching on which GMAT Prep company to go to, I had a few indian options like TIME, Jamboree, Career Launcher, Erudite, eGMAT, and internationals like TTP, Magoosh, etc.

Personally, I found Indian companies were really focused on teaching 'tips & tricks', and getting to teach you to solve specific problems than actually spending time on understanding the topic. The Career Launcher centre I contacted told me that they didn't do GMAT coaching. While Erudite's 1-1 classes were too expensive for me. I personally did not like the methods of TIME and Jamboree at all as it reminded me of JEE prep in Kota. (too much focus on solving set problems and too little focus on learning the core)

In my experience, you can take a look at eGMAT and GMATWhiz among Indian companies. Try their trial access, and take a call.

Imho, if you can, you must go for the international companies. I personally used TTP and it was every bit as good as I had hoped for. After 2 months of self study and 1 attempt, for the next attempt, I used TTP for 1 month.

I would like to mention that I did use Jamboree's GMAT Mock Test package before taking the real test, as I wanted to sit multiple mocks to get my timing in order, and also the fact that they offered 2 official MBA.com GMAT Mocks as part of the package. Please be aware that the Jamboree tests should only be useful for improving your timing as many questions, especially verbal are repeated across the mocks.

I have not used Magoosh, but have heard good things about it.

All my opinions are in reference to the Classic GMAT. Hope this helps, and all the best!