Like/dislike systems are unambiguous. Either you generally like something, or you don't; you can't have both. With enough votes one way or the other, you can get a sense for just how much people generally like or dislike something.
Rating systems in general are ambiguous; my standards are likely different to yours, and to Bob's and his will likely be different again to Bill's. For instance, I know several people who will never give out a 5/5 because they believe philosophically it is impossible to score perfectly. Others I know will just hand out 1 or 3-4's on principle because it's easier than trying to rank properly
One thing you need to be careful about if you do go down the like/dislike route and then want to generate ratings based on those votes is that you don't start generating them too soon. Basing a rating off say 5 votes means that the 6th vote carries a lot of weight and could potentially shift the object 1-2 stars on its own depending on the layout of the barriers.
For instance, you have 5 votes. Your breakdown is say:
5 stars: >= 90% likes
4 stars: >= 75% likes
3 stars: >= 60% likes
2 stars: >= 45% likes
1 stars: >= 30% likes
0 stars: < 30% likes
At this point, an extra 1 like or dislike would shift it an entire star rating (
1/6 = 17%)