Nostalgia might have been the main reason why i bought the TR-06. We used it back in 1986 when the drumatix was all we had next to a synth. It was pure fun. A friend of mine argues that with today's computers, this machine has become more or less obsolete. While i do understand his point of view, i do believe that the TR-06 still has that unique way of working which is different from DAW's and VSTi's imho.
If you expect a lot of sounds, you might be disappointed as there are only a few. Roland has put a few more inside compared to the original, but it's still not much. Of course there's a lot of alternatives that contain all the old 606, 707, 808 and 909 Roland sounds. I think the only true advantage lays in the hardware-way of working, not in having a lot of sounds.