By modern standards, these Voigtlaender lenses can't be classed as expensive especially the Skopars. These can be had for a few hundred $/€ depending on where you live. Presently I own the 35 and 50 f2.5 lenses and both perform well. As I've stated before I don't use either on the A7 / A7r comeras but they fee quite at home on the A7s and perform best on APS-C or M43 sensors.
What attracts me to these lenses? Well it's just their signature and is not restricted to the Skopar series. I like using all of the Voigtlaender lenses and I do own quite a few of them. If you haven't tried one of these lenses before, why not just rent one for a few days if you can, you'll be pleasently surprised I'm sure.