We live in a generation that is characterized by gross superficiality. One of the expressions of this superficiality is that some of the the rabbis who are very popular are often not on the same level in learning and spirituality as some rabbis and talmidei chachomim who are less popular and well known.
It is similar to the difference between going to a less competent doctor vs. a more competent doctor. One might get treated well by the lower level doctor but it won't as effective as the treatment of the greater expert. So too, the dimensions of spiritual and intellectual elevation are decreased because people often follow those with more style than substance.
My eitza is to follow the true tzadikim and masters of the Torah and look less to the popular-appealing-to-the-masses-type-personalities. Of course, they have value as well and shouldn't be completely disregarded but one must remember where the real emes resides.
Ruchniyus and true gadlus are not gauged by popularity levels.
ודי לחכימא.