I would suggest the advantages of using UAVs would obviously be the reduced risked to life of your own and cost effectiveness as opposed to that of Manned aircraft. You invest a lot of time, money and training into a pilot and you take the risk of losing that if he is of course killed. Once you have a pilot then you have to recruit and train PJs to protect your investment. So there is a whole lot of human capital at risk. Also you have the controller of an UAV in a safe location able to make decisions without the additional stress of open combat and potential loss of life there by effecting his decision making skills. Of course all of this would only apply for aerial to ground operations because I do not believe we are anywhere near having a UAV capable of competing in a dog fight with a trained human. The disadvantages would be the fact that the UAV has no morality nor does it hold any allegiance therefore it will do whatever it is told by its controller. If there is the possibility of hacking or seizure by an adversary that would be a serious problem. I believe technology is vitally important to the future of warfare and I would place an incredibly high value on the recruitment of those capable of serving in such a capacity and the kidnapping or assassination of the most brilliant minds of those whom we cannot turn that belong to a foreign power.