The see some of the (dare I say it) half a**ed builds out there and make their minds up based on that. I think that's why many people out there kinda look down on Pepakura as a realistic method to produce quality costume pieces. However, it still takes a lot of work and patience to make a Pepakura piece GOOD! Many have give up on Pepakura projects as they hit a wall during the filler/sanding process and give up. Especially for those who have no sculpting skill or access to CNC or 3D printing tech. I will add though that Pepakura is a great tool. I used Rondo for my Mando armor but for my Mando lid and Snow Clone I used standard filler as I hadn't discovered the Rondo method.
Works well for smoothing out large areas and domes! Saves a heap of sanding and waste of filler too. I didn't discover it by myself(can't take credit for that), I read about it on the 405th. The filler and resin are both polyester based so the hardeners are compatable in most cases. It's basically Bondo/filler mixed with fibreglass resin in a 1/1 ratio. Some people call it 'Mud', other(such as myself) call it 'Rondo'.