The TD9 sounds in comparison weren't too bad Vex'ed when compared to the TD15 at least that's my first impression right now with the evolution's pack although the cymbals definitely sounds better overall I think. There is a definite improvement in the dynamics (more "in between" notes) and play-ability of the TD15 with the supernatural sound engine and what not, especially with the VH-11 foot splashes are easier to trigger too. Its great being able to use the TD15 as the interface for triggering and a question i had before was can i trigger the PC sounds and 15 at the same time which i can. You can also control the volume of the sound coming out of the Td15 from the PC which is pretty cool as well to blend the 2 sounds. There are also of course more editing FX options obviously in the 15 which is really nice.
The negatives of the 15, for one is not being able to import the backups kits separate from the pad settings which i can see is going to be a real pain as i use it more and hopefully will be resolved in a future update. The second thing is the lack of different instruments, especially china's and splashes, they have 1 of each out of 500 sounds which is horrible. It also bothers me that the volume knob on the front as far as i know only controls the output volume and not the head phone which is what i need to adjust most of the time. Instead i have to reach around the side to adjust the tiny knob they have there for headphone volume.
Lastly a little question for the VEX team is why only 1 setup (1 backup file) for the Evolution's Pack?? The TD9 had 2 for each pack for different setups as i would like the AUX channel to be either a china or splash or effects cymbal or some sort but that's not included in the Evolution's pack.
Overall I think the TD15 is a nice upgrade if you can get it at a good price used but sounds are a little disappointing and hopefully Roland has a TD15v2 on the horizon.