I think using personal networks can be very helpful. However, there are two significant drawbacks. One is that, unless you have an extraordinarily large network, you really limit your search to people just like yourself. Sometimes it is useful to have an employee that has a slightly different network, has life experiences different from yours, brings a different point of view to the job. The other is that, although you may get someone who is pretty good and fits well with your team, you miss the chance to get the best person for the job. Personally, I would use a combination of resources. By all means, use the personal network. Lots of times that will identify someone who is not necessarily looking for a job. You just shouldn't limit yourself to that exclusively.