I can somewhat agree with /u/spaghettisburg. If you really have no idea or no clue what you're doing and just want someone to make you feel like you are getting your hand held through the whole process than it may be something to try. If I was to have to it all over again I would not have used them.
I will listed out my reasons for not liking their service. But it still ended up being a long read so...
TL:DR They screw up my application, gave me wrong info, didn't really help and constantly got my name wrong.
GoGo sent my application to the wrong school. To be fair I did choose one school and then later found a better fit for me and changed my mind. But this was very clear in many emails and confirmed by GoGo well in advance for the application due date. I only found out they did this from a random email from me checking up to make sure all my info was in order and I get the response that they "made a grave mistake." After the fun correcting that and applying to the correct school, they did not do anything more than forward emails from my school who did all my paperwork, applications, VISA and corrections. I would almost always get the info on the end of day Friday from GoGo so if I would always have to wait over the weekend to ask any questions or if there was any problems.
They gave me the wrong start date for my classes which I thankfully was talking with my school directly at that point due to all the screw ups and got the correct date from them.
They provided almost nothing as far as accommodations go for Osaka. If all they were going to do was browse oakhouse listings to send me I could have saved them the time wasted. Again talking with my school directly was a much better result.
They constantly got my name wrong despite having copies of my ID, passport, diploma, applications, emails and etc. I would correct the GoGo rep and she would say sorry every time and then get it wrong again the very next time we communicated.
Some of my classmates that also used GoGo had some not so great experience as well. Though not as drastic a fuck up as mine.
I would recommend finding a school you like and talk to them directly first and see what help they will give you. If you still feel you need further help then maybe try GoGo.