In all honesty - and you may just have an exceptionally long torso and really long arms - the sizes of those bikes sound like they are on the verge of too big. If the top tube/effective top tube is too long, you won't be able to get your weight behind the seat on downhills to avoid going over the handlebars. In addition, particularly with the 29er frames, if your legs aren't long enough you won't be able to get the seat high enough and still reach the pedals.

Have you tried any of the bikes a size smaller? That may leave you more leeway for adjustments to make the bike fit better.

I'm 5'7" with long arms, long legs, and a long torso, and I prefer a "small" frame for most unisex 29ers. I'm on the verge of too stretched out on my 17" Cannondale 26er frame - I would prefer a top tube about a half inch or so shorter.

I do love a 29er! And your bikes are in the same price range as my original purchase. I wanted a new one pretty quickly though