Not long after our daughter was born my wife and I decided that we should eventually get a running stroller. Since they are not cheap, my wife initially scoured the internet for used Chariot strollers. Unfortunately, everytime she thought she had found a good deal the stoller had already been sold. This only served to convince us that buying a Chariot was a good choice.
Once we settled on buying a new Chariot the only debate left was whether we should buy a single or double stroller. We ended up going with the single CX 1 model http://www.chariotcarriers.com/english/html/cx.php as we both felt that we would be less likely to run with two kids in a stroller.
Once our daughter was old enough to run with in the stroller I began taking her with me on my weekend runs. I started out taking her on runs of about 10-15 km but it was not long before I took her for longer runs. To date, I think the longest distance she has travelled with me is 26 km.
In terms of running with the stroller, I did not find it as much as an adjustment as I expected. It is certainly more of a workout than running on my own but I am still able to keep up with my intended paces.
The biggest benefit of having the running stroller is that it allows me to spend more time with my daughter. It is fun to watch her sit and keep herself entertained as I run.