I'm sorry but I don't know much about Kristal, but I will definitely vouch for n-Track as being worth it.
Up to 80 tracks.
DirectX and VST support.
DXi and VSTi support
Rewire support.
Volume envelopes and automation.
Multi screen support.
32 bit float mixing.
The list goes on and on.
Awesome forum .
Great support site Audiominds.com .
$45 US for 16 bit version.
$69 US for 24 bit version.
Grab the PDF manual while your there. The manual is slightly dated to the latest version of the program, but most of it still applies. Anything else can be answered via the forum.
If your current software does all you need, why spend money?
But if you find yourself frustrated because you can't so something you want to do, or frustrated because it's difficult to do what you want to do, then spend the money to get something decent. And N is way more than decent.