RE: Need Info about aircraft
1) depends, i prefer arf's because i don't have much building experience/or the time to build one, they are fun to build, and i don't suggest buying one that someone else built. you should take pride in the fact that you built the plane yourself
2) couldn't tell ya honestly.
3) i have built a couple of my own planes. i took many weeks just on covering, i like to do my own design, not what is already on the market in an arf. however, you can also re-cover an arf to add your own personality into the plane without building it yourself.
4) like i said, if you want a custom arf, i think it is better to do your own custom work. you can add/subtract features on an arf. for example changing the landing gear style, re-covering, even changing certain characteristics of planes-i.e.-diff. wing shape/total different plane wing(not always easy to fit to the plane, but can have advantages) stuff like this makes it your own unique custom plane, not a custom plane that someone has reproduced and sold 100x over.