Until recently.
By a chance recently, I listened to a radio play version of "Gaudy Night" one of her later novels with Ian Carmichael (the man above) playing Wimsey. I thought it was interesting, but a little weak in terms of the mystery itself. It seemed to me a romance story (between Wimsey and Harriet Vane) with a mystery thrown in. Anyway, on Twitter, Jennifer Quail, an author and fellow Jeopardy! watcher (although I am in a down period for that) said that she preferred Sayers to Christie. I responded with my beliefs, and she gave me the name of what she thought was Sayers' best mystery "The Nine Tailors" I told her I would give it go.
Now, knowing me, I soon entered the rabbit hole and burrowed my way through Sayers' novels by adaptation. There are not many, as compared to Agatha Christie. The two main ones were televised stories with Carmichael in the 70s, and Edward Petherbridge in the 80s. To me though, Carmichael is the definitive version for the most part. Lord Peter is an aristocratic charmer, and Carmichael plays that to a tee. Petherbridge did only the later novels with his wooing of Harriet Vane and he is good, but Carmichael is definitive for me, it seems. He did those later novels too on radio and is very good in it as well.
As for the Sayers-Christie debate, it seems to me that Sayers was a better overall writer than Christie. Christie has gotten a bad rap of having characters that are essentially cardboard cutouts, and Sayers does not have that problem. Wimsey is shown in later novels having suffered PTSD episodes from WWI. However, what Christie lacks in characters, she makes up for in plots and crimes and that is where she stands above Sayers and basically everybody else. So, while Sayers is a better overall writer, Christie is a better CRIME writer. Not to say that some of Sayers' plots are bad; "Have His Carcass" is the most Christie like of her plots. But they seem to easily point to one suspect relatively near the end, while Christie can keep you guessing all the way through.
I am not yet thoroughly done with this rabbit hole as there are some warrens still to explore, but I wanted to write this down so that I can show that I am not above learning something new and exploring other things that are outside my vein. And it has been an interesting experience so far.