Not a direct comparison of MongoDB and CouchDB, but a list of what Riyad Kalla considered important aspects of each of these solutions.
There is one bullet point that sounds a bit off:
Read Performance - Mongo employs a custom binary protocol (and format) providing at least a magnitude times faster reads than CouchDB at the moment. There is work in the CouchDB community to try and add a binary format support in addition to JSON, but it will still be communicated over HTTP.
I’d venture to say that the “at least one magnitute faster” should happen only when reads in MongoDB are not touching the disk. Otherwise, I’d like to see some data showing how the over-the-wire MongoDB custom protocol and BSON provides 10 times better results than HTTP and JSON.
Riyad Kalla also added a section about Redis and how he finds it useful in most cases in a caching capacity or queue capacity.
Original title and link: Should I Use MongoDB or CouchDB? ( ©myNoSQL)