Ergonomic Kneeling

I'm Looking For A Kneeling Stool To Use In My Home Office - I'll Be Using It 8.25 Hours Per Day Four Days A Week So Not Really 'light Use'. I'm Larger Than Average So Want Something Sturdy That Is Not Going To Break!

But The Question Is - Is It Better To Buy A Wooden Kneeler Or A Metal One? One With Manual Adjustment Or One With Built In Height Adjustment (like A Standard Office Chair)?