I will take a wild guess and say they are not comparable at all in performance, other than them being similar in magnification range. I own neither, so I have no personal bias, but I’d be willing to bet the Swaro is twice the scope (optically) since it's almost twice the price ($1,299 vs. $799 on EuroOptic).
The Swaro Z5 is basically Swaro's version of the Zeiss V4. The exception is the Swaro Z5 is assembled in the USA (same as the Leupold), just like the old original Zeiss Conquest MC scopes were, and assembled from imported parts. While the new Zeiss V4 scopes are fully built in Japan by LOW with ED glass. I don't know where the Swaro glass is made, I couldn't find out that info, so not sure they're sourcing it from the "budget" line of Kahles scoops (Kahles has been owned by Zeiss since the 70's), or if they're importing it from Japan or another company in Europe? The Leupold VX-5HD just said it was made in the USA, and didn't say anything about where the glass is made.
So, honestly, i'd say a more fair comparison to the Swaro Z5 would be the Zeiss V4. Both of which are similar in price and specs, and twice the price of the Leupold.