'Chocolate Chip' is not variegated so you don't need to worry about reversion. And it does grow quite a bit less aggressively than the species. But it is a spreading groundcover and if well-sited, will happily consume real estate, although not the point where it will overwhelm other plantings. And it is easily removed if growing where it's not wanted.

I agree, it is a mix of color not variegated, spreads nicely and is a joy.

Here is a link that might be useful: Easy Shade Gardening