Panspermia is not cheating. If we believe abiogenesis to be vanshingingly unlikely on any one planet, panspermia paralelises discovery of a solution.
If surface abiogenesis is unlikely, panspermia is more unlikely because it needs the former, plus a way for the spores to survive in space, the travel of interplanetary, maybe interstellar distances, atmosphere re-entry and developement in a new environment.
Another factor is that, if we accept the current estimations for the age of Universe and the fact that some elements only are present in second or third generation star systems (because they were formed inside novas), we could be one of the first guests to the party. Panspermia would place abiogenesis even further in the past.
The only scenario in which panspermia would be more likely is that some components that are needed for life can only appear in space and develop on the surface.
That's not to say that panspermia is in itself an absurd idea, actually the fact that some elements need to be created inside stars means that we're somehow children of the stars, it just happens that panspermia isn't a great substitute for abiogenesis. An amplifier, maybe.
>> If surface abiogenesis is unlikely, panspermia is more unlikely because it needs the former, plus ...
That depends. Panspermia gets a huge multiplier from distributing the number of planets and eons on which abiogenesis might have happened just once. So it depends on the relative impacts of very different factors - neither of which have been well quantified.
If panspermia had ever been feasible, it was likely more so in the earlier universe. Personally, I prefer it because it seems to follow the Copernican Principle.
Well, that's... correct. I still think that it's less probable, but I have no way to prove it :)