Hi, 

During preparation of NEET attending tests and solving as many mcqs as possible plays a vital role. 

I personally had given the aakash tests and the questions were standard. 

As for which test series is better, its not possible to pick out the better of the two. 

Every institute has its team of faculties who help prepare the students to crack the entrance exam. So be it aakash or goal every test series will give u different set of questions and help brush ur knowledge.

So you can opt for either of it. 

Just make it a point that you are clear with the theory and have your basics strong. 

All the best.