The 135mm is probably the best portait lens in the TLR selection. Long enough for tight head shots without exaggerating features, and short enough for domestic spaces. It makes a useful two-lens pair with the 65mm for general photography.
However, I find the 180mm is a better general purpose long lens. If portraits are your thing, go for the 135mm. If it is going to be too short for a lot of things, decide where you want to compromise (or get both).
The 135mm has a quirk that disturbs some people - the shutter is mounted behind the optical elements, and the blades are exposed.