They have comparable records and Swann certainly isn't England's greatest ever off spinner.I'm not really sure why the question of whether he is better than Swann or not is an issue, Swann was a very good bowler, who like Lyon, got better as he got older. So in simple answer to your question, yes I think Lyon is better than Swann and this is a good effort because I also thought Swann was really good.
Swann was very good, as is Lyon, but neither of them would be in the conversation with the sub-continent greats or Warne.
My issue with Lyon and the 'greatest' tag is that he is far from the greatest and his records are the natural result of playing so many tests (again no other alternatives because SOK's issues). He's decent yeah but I feel when we look back at Lyon's career in a few years we will all agree he was very overrated.