I think it all depends on the your purpose of buying.......
If you want to use it for playing, go for DF03.......coz' it is a new model, the spare parts support is not a problem........
If you just buy it for collection......not for playing.......you can consider the frog & hotshot.......but you need to be prepared that the spare parts support will not last long.....coz' both are re-released models.......
One more point is, if you not a tamiya die hard collector, please forget about hotshot.... Its only for professional.... Do you remember a TV shampoo commercial.....