Currently have 3 cases and I am in the same situation as you. Still searching for one that I truly like.
Modal reversible folio case: it's good but it makes the phone feel bigger. The case has magnets. You can use the phone in landscape with this case but since there aren't many apps updated, it's kind of useless.
Insignia silicone : I just bought it because my phone came sooner(on sept 22) than expected and was waiting for spigen to ship my Neo hybrid. I don't like it. It's pretty basic.
Spigen Neo hybrid yellow:for me, this case was the best for the iPhone 5, so I thought it will be good with the 6 plus but no. First the case need the stabilizers for the buttons to work correctly and it's kind of loose on the side. The one for the iPhone 5 have a perfect tight fit.
I think I will try the apple silicone case. Many people like you say it's the best one right now.
I love the Apple silicone case. Yes the bottom is open but all the other pluses outweigh that. The Apple is refined, fits perfectly, great grip, washes up nicely and gives decent protection. I have the white one and absolutely feel it is the perfect case for me.