If you are looking for a SMS marketing campaign tool, SimpleTexting may be a very good option for either individuals or small to medium size companies.
It has a set of powerful features while remains easy and intuitive to use, also, there many options for customer support either via email, phone or live-chat or online by reading articles or watching how-to videos on their knowledgebase.
The main features include: schedule messages to be sent at any time, unlimited keywords (with any plan!), importing your contacts, auto responses, support for 2-way communication with your contacts, voting/polling and creation of unlimited users and groups.
The user interface is simple and easy to use, navigation is intuitive and doesn't bombard you with unneeded sophisticated options.
SimpleTexting has very competitive rates (mainly if considering the unlimited keywords), and offers a free trial.
The main feature that is missing from SimpleTexting is the support for MMS, which means you can't directly add photos or videos to your messages (you can add links to external multimedia elements).
Another lacking feature is the report system, while you do get some reports (such as opt-in and opt-out contacts), you don't get reports about delivery notifications and about keywords (which could help analyze your campaign)