Updating content after major upgrade from 5 to 6 (changes to production site need to be reflected in dev environment)
I have not found a better alternative to migrate module till date and I have done lots of migration including ubercart order migration. It has served me well for:


ASP.Net (MSSQL server) -> Drupal migration
D6 -> D7 Migration 
Rails (MySQL) -> Drupal Migration


There are tons of other modules like node_export, views bonus pack, uuid features, deploy that will let you export content out of drupal site but nothing scales better than migrate module. Having said that, its some effort as you need to write your migration classes, but it comes with excellent features like:


Incremental Migration ( you can test your migration class, with small subset of content)
Rollback ( In case you realize you missed something ) 
Solid drush interface. 


Also, once you get a hang of it you keep appreciating the fact that it always work. It knows what has been imported, it reports on warnings during migration, gives you a status update on your migration. Can't recommend it enough!! and the best part is minimum downtime, you keep syncing content till the last moment.