Typically switches fall into three categories unmanaged, smart and managed, each adds an extra level of functionality and complexity as you move up the food chain.
Unmanaged Switches are the simplest way to build a network and let it pretty much run itself. They are designed to enable plug-and-play connectivity, which makes them perfect for small businesses which don't have complex networks or dedicated IT department that manage their network or have a requirement for simple network connectivity like to share resources. These typically have no network management capabilities - CLI or Web management.
Managed switches allow network administrators to monitor and shape traffic across the network, introducing redundancy and access control. Typically managed switches are deployed in networks with a large number of users or devices; and/or company's using bandwidth-hungry applications, where performance and reliability need to be maximised and security enforced. These switches always have a CLI and Web management.
Smart or web-managed switches have many of the benefits of Managed, as outlined above but without the complexity or cost. Smart switches are designed to provide easy configuration through a web management GUI. Ideal for users wishing to build small- to medium-size networks but who don’t need all the advanced features necessary for large-scale corporate deployments. Some higher-end Smart Switches also incorporate a subset of Managed switch capabilities such as a CLI, centralised management, stacking or some limited Layer 3 functionality like static routing allowing for scalable network design. D-Link's products support some unique features such as Auto Voice and Auto Surveillance VLANs to prioritise traffic from VoIP phones and IP cameras in the network.
It is important to bear in mind that unmanaged switches are the cheapest switches to deploy if you dont need network bandwidth management. This is typically where the Trendnet products sit. Managed switches have a lot of capabilities to manage and control the network traffic. We have seen the Smart switches replacing unmanaged switches in the Surveillance market here in Europe due to the price/performance of the devices.