I would go with a Ute. Once you add in a kid packs fill up fast. A Ute can get almost as small as an Umlindi, but an Umlindi will never get as big as a Ute. Plus as you add weight, and maybe a kid, the more you will appreciate the lifters.
Oh man now you made my choice even more difficult. I was looking at a Ute but it seemed like too much pack for what I needed right now. My daughter is only 2 months so it will be a while till my girlfriend is comfortable taking her with us.