HI mate , you say you want to carry a go pro, so really 450 min on size , octicopter or hecticopter are the most stable , but a good well built quad can be very stable too try and keep it light as weight eats battery , if it weights 1000g your need about 2500g of lift so you dived by motors ,so if its a quad then each motor needs to give 625g thrust each , this can be done by low kv motor and large props , so if it has 6 or 8 motors each motor has to lift less , also if a motor fails on a quad it will crash but 6 or 8 motor can still fly with a motor fail
list to look at for a quad will read
1 x frame
4 x motors
4 x esc ( simonk flashed as they make the quad smooth to fly )
FCB ( flight control board) kk, naza,nase32,wii etc
GPS ( if your flying FPV) if you want gps this will govern what fcb to have
Fpv system
4/6 channel transmitter and receiver
wire and heat shrink
props 2x cw 2x ccw carbon fibre are better then plastic give a smooth flight
camera mount with servo gimbal
Now where you live will govern where you can buy from, Hk do clone frames and some nice one of there own ,if you need to keep props out of the camera view then H frame or dead cat frame , but once you go 550 or over you should be ok and not have props in the shot