The viet peppers go green to orange to red. The orange stage is only a couple of days before I would call it full red, though they never get to the deep fire-engine hue that the goatsweed does. Also, the early spring sets are a little fatter at the base, the pods that set after the weather fully warmed are very skinny with a pointy tip (also a lot hotter!)
The c. frutescens is fully ripe at orange, they never go full red. I love this plant! It produces gobs of pods with a nice fruity flavor and decent heat level. It was flowering and setting fruit last year all the way through the hottest part of the drought, 105 degree days! That is way above the "normal" temp that peppers are able to pollinate at. It also made it to almost 6 feet tall from seed, and there was about one month where it was heavily shaded by a cucumber plant that slowed it down considerably.