From a scientific point of view, the concern should not lie so much in their thermal conductivity as both are metals and you can expect similar thermal properties.
SS is known to have problem with welding. If connecting the pipings requires welding. SS is usually avoided, as welded SS will rust when the chromium layer gets removed.
Why SS is rust resistant is bcoz of the chromium layer. Imagine bending SS, not only will the protective chromium layer gets thinner. It may even become incontinuos. When a protective coat becomes incontinuos, its as good as one without any protective coat. Think: a scratch on a coat of paint over iron.
Tougher metal like SS, when bent, The mechanical stress build-up is also higher. And corrosion (rust) usually attacks regions of higher mechanical stress concentration (google: stress corrosion)
These are some stuffs I recalled from my uni days.
