We’ve heard from several clients and through the grapevine that QuickBooks 2013 has significant performance problems, particularly with large databases. What constitutes a large database depends on who you ask, but I would generally say anything above 500Mb (0.5 Gb) is a large database. This has been reported on Pro and QuickBooks Enterprise Solution, and may affect other editions.
For now, the issues we are hearing about suggest that there may be a fix on the way soon. The performance issues are severe enough that I’d expect Intuit to have a fix for this soon. We don’t have any inside information, though.
For now, we recommend that you hold off on your 2013 upgrade unless your database is small or you have a very big need for a 2013 feature. I will post more information as we get it.