If you have a computer, software can emulate these and do more. The only advantage to having those boxes are the immediate sounds in the 909 or 7000 and the pads to trigger sequences, or program drums. If you have a computer, you could use, say Battery 2, and get an akai mpd16. Software is defenitely the cheaper way to go.
Also, on the TI you will need a computer to program your own arpegiations via its editor. Some food for thought.
