I enjoyed the discussion of hstore, json, and xml, but I thought the benchmarking was a little silly. I suppose if I really wanted to keep my database on a laptop it could be useful.
i also think that the benchmarks are useless.
imho there are two reasons to choose mongodb:
2) developer friendliness as you are very flexible
i’d be interested to see how benchmarks look when you have a few TBs distributed over 5+ machines with ssds.