I only used Kaplan and it served me very well too. My biggest recommendation is that if you go with Kaplan, strongly consider buying the in-person class. While it's expensive and the class may feel slow to you at times, it's the only way to get access to their "MCAT Channel" which is a hub of both archived and live hour-long, content review sessions. It's an incredible and underused resource. The in-person class also adds a degree of accountability which can be useful if you find it difficult to motivate yourself to sit down and study. I wouldn't just buy and read through the review books and expect to nail the MCAT. It's the amount of practice and time you put towards the test that can lead to those 90th+ percentile scores.
Also of note: You might hear people complain that Kaplan practice exams are too hard and artificially deflate your practice exam score. While the latter is somewhat true, don't think of the exams as being "unfairly difficult." Rather, think of it like "strength training" for your brain. I walked out with a smile on my face on test day because it felt substantially easier than the many practice exams I had used during my "training."