Yep, Renata way better.  However you'd have to push your bikes down from Akatarawa saddle, its only 20min or so whereas you could ride all the way to Waiotaru.  Apparently you're allowed to MTB all the way to Otaki Fx from Waiotaru hut, then you could bike back across the Mangoane walkway and make quite a nice loop.....

Appropos of nothing: in 2000 after a rather big club party in Waikanae a family wagon was driven to Waiotaru hut and with the doors open we could drive it inside the hut.  I think we found some human poos there too.  Though these were unrelated it does highlight the ugliness of Waiotaru.