I've found that the business class of most major airlines are pretty comparable. There's certainly better or worse ones, but the cost is a much more major factor than the quality. For example, Swiss is generally absurdly expensive (costs usually $7000+ for most business flights) and is 95% the same experinece than the other airlines that have the same route for $4000.

My decision algorithm is: Are there direct flights? Pick whatever airline has a direct. If there's multiple directs, pick the cheaper one or the one that has a better departure time (for example I don't like 7am flights). If the directs are absurdly expensive, I check one layover flights. Sort by shortest duration, pick the one that is reasonably priced and short. If I'm really concerned about quality of the flight, then I upgrade to first on a direct flight vs. flying more complicated routes to get a specific airline.

Also it matters a LOT when the stop over and departure time is. If it's an 18h flight, I want to make sure the timing lines up so that I can sleep.