DVDDecrypter still works on many DVD's and has some advanced features (such as ripping individual titles) that are not found on a fair number of other decrypters. So, no, don't uninstall it.
DVDFab HD Decrypter is still free to use, but there are some issues for US citizens. Ask in our DVDFab forum for detailed instructions on the program, or wait for cholla to come back in here, since I am not a DVDFab user.
You should be able to compress a movie that is decrypted by DVDFab using DVDShrink. You will get higher quality results using DVD Rebuilder (there is a free version). DVD Rebuilder is especially good for compression of large DVD's, that push the limits of visual quality when using a transcoder like DVDShrink or CloneDVD.
DVD Rebuilder isn't as fast as DVDShrink, and DVD Rebuilder does not decrypt anything by itself.