I'm betting that the LP, despite having only 4 knobs, will be an improment on the Voyager as far as having real knobs/pots versus the Voyager's rotary encoders. In my experience this can make all the difference in terms of the "feel" of a synth. For people used to playing older Moogs, I think the LP will have more of the classic Moog feel and that will translate into it's overall playability.
The Voyager controls feel very solid and are very well built, of course, but theres no substitute for direct analog control over parameters. The Little Phatty will be even more "the real deal," if that's possible.