Move archive is superior in every single way to PST export and import
For instance. Say you have all items with a three year retention category that does expiration by archived date
If you use move archive, it preserves things like Archive Date, do even though you move the archive on 01/01/2012, items will still show they were archived on 06/25/2009
Meaning that on 06/25/2012, 3 years after archive it gets expired
Butif you import PST, it will have archive dates of 01/01/2012, meaning the item won't expire for another three years which could be breaching your own retention laws
Also if you have multiple retention categories for mailboxes, you have to export and split te PST's (one for each retention category, otherwise if you do one single PST and import it, everything gets archived with the same category
Just make sure you are on the latest service pack and you should be a-ok
https://www.linkedin.com/in/alex-allen-turl-07370146