These are quite good. But are very expensive.
Personally I tend to recommend using normal wired cameras and a DVR with a network connection or a video server. This means that depending on the model of DVR or server you can view 1 to 4 cameras via the internet. Some DVRs can have up to 16 cameras. Having more than 1 IP camera can mean having to remember more than one IP address to access. Also using normal good quality cameras and a DVR can work out cheaper and may allow you to have 2 or more cameras and a DVR for the same price as 1 decent outdoor IP camera.
You can also get DVRs with WiFi connection. So no need to connect to your router using a cable.