We installed cameras when we took a four-month trip to the U.S. and Canada. We don't have motion detection but we have remote access via internet. We would download playbacks for different things we could see that were of interest; the gardener hadn't cut the grass, the pool needed attention, the cats were fed and played with, etc. We were also able to catch a person who was vandalizing houses, I won't go into details on that, but neighbors who knew we had cameras contacted us. We downloaded the events, sent them via email, and the culprit was fired from his job.
It gave us some piece of mind and we found it very useful. We just had one camera replaced yesterday as the cable was accidentally cut by the gardener. When you're 3000 miles from home, it's good to see what's going on.
We have already talked about adding motion detection.