A VPN Tunnel connects your remote computer to a local (office) computer. The two computers can then talk to each other securely. This works fine if you are connecting to your server at the office and you have no need to connect to anything else. From your server, you can make provisions for accessing resources like other computers, printers and your VOIP telephone system - but you need to make those provisions before you can use your tunnel to access those resources.
A VPN Bridge connects your remote computer to your local (office) network. Your computer will simply appear to be wired to your local network. For the most part, you will see your co-workers workstations in your Network Neighborhood and your co-workers will see your workstation as if you are at the office. There are some exceptions to this; not everything will work transparently. Still, a bridge can be easier for users than a tunnel if only because you can securely copy files between workstations and print to any printer over a bridge without having to make any special provisions for each resource on the server.
There is an added cost for using a bridge, though. Many customers will find that their available network bandwidth is too low to support the added overhead of a bridge - so they opt for the more efficient tunnel instead.