Your are talking about many different device and calling them all range extenders. Some work horrible and other great. The best is to run a AP but that requires a ethernet cable from the main router to the remote "extender". The next option is to run powerline device. These are not commonly called externders but they do let you use your electical power cables as a ethernet. You then put a AP at the end and it works pretty good but powerline is still a form of radio and other electrical devices in your house can interfer. The worst so called extender is a wireless repeater. These greatly degrade the quality of the signal but do get more coverage. You would only use a wireless repeater when a really poor connection is...