CiderExpert's 1-5 star rating system is far from unique. From all ratings, we compuate an aggregate rating. While there is some use to this, it isn't as useful as you might think. A highly rated cider could be any of these:
However, there are very few ciders that have universal (or near universal) agreement that it is excellent (or poor).
If it's an overall excellent cider, you definitely want to give it a try! However in the other cases, if you don't happen to like that category, you might be sorely disappointed.
So the short answer is no. Sticking to highly rated ciders is no guarantee you'll enjoy your cider, and you're likely to miss out on a lot you will like.
There are multiple reasons why a cider could end up with a low rating, for instance:
With just looking at the rating, you have no way of knowing why a cider got a relatively low overall rating. You might find that you're a fan of ciders that are somewhat less popular.
The Top Rated list has ciders that have a sufficient number of ratings that the number is meaningful, and has the highest overall aggregate rating including all reviewers. This doesn't mean that everyone will like these ciders, but they are popular.
So don't read too much into this list, but these ciders are good bets when:
Soon you will hopefully be venturing far beyond this list!