I disagree about better looking personally but both are certainly striking and elegant. The Reverso is an itch that can really only be scratched with a Reverso IMO. Regarding servicing, both are Richemont group products and serviced at the same place, while the Cartier uses an off the shelf ETA or Sellita which in theory is more friendly for an independent watchmaker to work on, if you go official both are very expensive to service so I don't see that as a massive plus for the Solo personally. A recent example of either will be covered under a 8 year warranty so servicing might be a can you can kick down the road for a few years if you can stretch to a newish one.
This is a 1990s Grand Taille Reverso Duoface next to a recent Solo Auto XL.: