"This database is good at high concurrency writes" and "this database has very good write performance" strongly favors MongoDB. This is interesting because Mon

"This database is good at high concurrency writes" and "this database has very good write performance" strongly favors MongoDB. This is interesting because MongoDB has taken a lot of flak for their global write lock. Also, updating a MongoDB document can require moving it if it grew too much for it's allocated space, which is another thing that hurts write performance. I guess these things haven't hurt their public perception of their write speed as much as I thought.