Verbal traffic alerts indeed work very well. While SD algorithms do a good job in reducing the number of traffic alerts to those that are truly relevant, more often then not the odd traffic warning competes in the headset with

- SD's airspace and obstacle warning
- and radio traffic from one or more monitored frequencies

It would be a great idea to 'pan' the stereo image of the verbal alerts? Typically, the radios come in mono, i.e., dead centre. Readability of parallel messages could be much improved if airspace warnings came slightly, say, from the left, and traffic warning slightly from the right. 

The spatially distributed Audio pops up once in a while, but it is not a Holy Grail. I have flown with the technique in fighter jets, but we were thoroughly trained for using it. Private pilots are usually on rather low training level and there are hints the distraction of spatial information within Audio is too much - especially in IMC the often accompanied head movement may outweigh possible benefits.