CTP6 is now available for download here. This has all the functionality of the final product and amongst the new stuff for this CTP are:
- Data compression.
- Integrated full text search – indexes are now part of the database making for easier backup and faster mixed mode queries.
- Filtered indexing - indexes with a where clause.
- Partition aligned indexed views
- Policy based management (the feature formerly known as declarative management framework)
- Sparse columns so you can many more columns in a table
- Gauges in reporting services
One thing to note is that the link above still looks like the November CTP but does actually link to the February one, and the TechNet and msdn pages will change over the next day or so to reflect this.