Recs.
Updated
SpecsUpdate
Pros
Pro Quickly add rich text
Remember The Milk offers Smart Add – shortcuts that allow you to quickly add advanced information to a task. For example, you can quickly add a due date, set the priority level, add a tag, set repeat times, add URLs, and add notes to your tasks. For the full list, check out How Do I Use Smart Add?
Pro Manual sorting
Manual sorting is available on both the web app and android, allowing prioritization of tasks. This can be particularly useful for shopping lists, where you can put all the meat together, and all the cheese together etc. to make it easier to skim through when you're in the store.
Pro Location-based notifications
You can set locations for each task (for example a specific store, or a general location like 'near the beach' for shell collectors), and RTM will remind you when you are near or in that location. This can help keep your daily list uncluttered and remind you of errands you might have forgotten.
Cons
Con Free version lacks features
Mobile reminders, subtsaks, offline mode, Microsoft Outlook sync, priority, and more features are limited to the paid version ($39.99/year). To see the full list of restrictions, check out this page.