Developers may be biased towards Stripe because their API is among the best, and likely best-documented. (I had run into issues with the docs before, but was able to get to actual humans to resolve them. Eventually. Their first line support is just as bad as is described in any dilbertesque horror stories about outsourced support drones, giving you canned responses and having comprehension problems all the time.)

Now my theory is that Stripe will be a tad more inclined to help developers who help them build their empire via integrations and platforms and such, while actual merchants are a dime a dozen (in their eyes). I also have a perception that they have become way more MBA-aggressive in the recent years.