A "really" good Web Host should "really" fit the needs of your Drupal Website and Drupal as a CMS. After uploading or/and deploying modules in your Drupal Website, you've got or will probably get this error, typically when trying to display Modules page:

Fatal error: Allowed memory size of .. bytes exhausted at ... (tried to allocate ... bytes) in ...

In order to avoid having this type of problem, a Web host offering sufficient PHP memory limit is greatly advised. However, it depends on how many and which modules you upload.