I don't think there is anything wrong with getting one artist to do full cohesive and integrated pieces. Those tattoos are quite spectacular.
I think though when you mix up styles, work with different tattooers you get a different experience and new perspectives. The tattoos become very collaborative between the receiver and the maker. You get to keep going on the neverending journey. You may make some mistakes, you may make great decisions, but the mash up of style and experience makes for very very interesting and real tattoo collections with many life lessons and realizations woven into your skin. You become a living quilt or "colouring book" as i say. At least that's what I'm going for.