If you are doing any work with FAST Search for SharePoint 2010 and need to index database content (e.g. SQL tables), as a general rule of thumb you should use BCS for this.

FS4SP does have a JDBC connector that is quite capable of indexing database content, though don’t just use this because you have FAST and think you need to.

The reason here is simple - you will have a much simpler migration experience to SharePoint 2013, as the JDBC connector is now no longer included.

Ok so the key differences between SP2013 and Fast Search for SharePoint 2010 are officially up on TechNet.

In summary, a number of features have gone.  Some people may be upset, though overall I think the majority of changes make sense because it simplifies the platform.  FAST for SharePoint (FS4SP) included a number of features that were baked in from FAST ESP (the standalone, pre-Microsoft product) and became redundant when SharePoint was added to the mix.

On FAST ESP, there used to be a technique to get back all documents in your index - enter the minus character, followed by a term that wouldn’t be in your index.

For example: -394kidfdkadkfl2k2

This would bring back all documents.

In FAST Search for SharePoint 2010, this does not work.

The trick instead, is to simply enter the hash character ( # ) by itself / without the parenthesis in the search query textbox.