CC 1.8, which has been put on google play will be available sometime in the next couple of hours, should be a significant improvement for you, in all of startup, grouping, sending books, and uploading metadata. For example, with 1,800 books on my galaxy nexus, the "sync" when connecting finished in 3 minutes. Sorting and grouping were nearly instantaneous.
Please do note that the first sync after upgrading to 1.8 will take a while. There have been some changes in calibre that require it to re-download the metadata for all the books on the device. This will take around .5 seconds per book. Future connects should not require this extra time.
There are progress bars now for metadata upload and download.
