What are the pros and cons of DynamoDB with respect to other NoSQL databases?

Question

We use MongoDB database add-on on Heroku for our SaaS product. Now that Amazon launched DynamoDB, a cloud database service, I was wondering how that changes the NoSQL offerings

Answer 1

Pros

1. Lightning Fast (uses SSDs internally)
2. Really (really) reliable. (chances of write failures are lower)
3. Seamless scaling (no need to do manual sharding)
4. Works as webservices (no server, no configuration, no installation)
5. Easily integrated with other AWS features (can store the whole table into S3 or use EMR etc)
6. Replication is managed internally, so chances of accidental loss of data is negligible.

Cons

1. Very (very) limited querying.
2. Scanning is painful (I remember once a scanning through Java ran for 6 hours)
3. pre-defined throughput, which means sudden increase beyond the set throughput will be throttled.
4. throughput is partitioned as table is sharded internally. (which means if you had a throughput for 1000 and its partitioned in two and if you are reading only the latest data(from one part) then your throughput of reading is 500 only)
5. No joins, Limited indexing allowed (basically 2).
6. No views, triggers, scripts or stored procedure.

It's really good as an alternative to session storage in scalable application. Another good use would be logging/auditing in extensive system. NOT preferable for feature rich application with frequent enhancement or changes.