Best means in this case: Easy to install, configure & handle, flexible and reliable. Furthermore this attribute requires that the module is “Under active development” and that a stable version for Drupal 7 is available.
Fivestar is a very simple rating module that provides the possibility to rate items with stars or similar items. The items to be rated are added to nodes using fields, which can be configured to be displayed in various ways. This gives you the possibilities to rate various items or even to create online forms for evaluations and assessments with different questions to be answered.
"The Fivestar voting module adds a clean, attractive voting widget to nodes in Drupal 5, node and comments in Drupal 6, and any entity in Drupal 7. Developed by Lullabot and an officially supported module in Acquia Drupal. The Fivestar module depends on the Votingapi module."
The Rate module offers more possibilities than the Fivestar module. First of all you can choose between different ways to vote (see below) and secondly you have a vast array of configuration possibilities. The rate module works with widgets instead of fields. This has its advantages and disadvantages. An important advantage is, that you can instantly and centrally enable different voting possibilities for different content types. A disadvantage might be, that by default you can't display the voting within the content of the node (only above or below the content).
"This module provides flexible voting widgets for nodes and comments. Administrators can add multiple widgets. By default, there are 8 widget types to choose from: Thumbs up, Thumbs up / down, Number up / down, Fivestar, Emotion (this makes me mad, angry...), Yes / no, Slider and Custom. By using "custom" you can customize the rating buttons and Voting API mode. Widget types can be extended by other modules."
3. Star Rating
The Star Rating module is not meant to be used for user ratings. As such it is a nice solution for review pages, where the rating is provided by the author of the pages or the articles. For example, if you are creating a review web site and you want to add various star ratings within a node, then this module would probably be the best match. The configuration of this module is done in a very similar way as the Fivestar module, what means that the items to be rated are added to nodes using fields.
"Star Rating is a simple module that provides star rating field and display formatter using Drupal 7's Field Type API. It is inteded for the rating only by the author of the article (node). Of course, you may be able to do this with Fivestar module and other voting/rating modules, but unlike most of them, it does not require other modules such as voting API module. It's born to be simple but good enough for those who want star rating only by authors."
While the Fivestar and Star Rating module have quite a stylish appearance, the Rate module looks a little old fashioned and probably needs some modifications to look nicely.