I think it breaks down into three parts. Durability, sound and feel.
Soft gel is going to give you the most natural feel since it is thin and very flexible. Almost identical to the natural feel of your nails (assuming you make sure you or your nailist applies a relatively thin coat.)
I think tone comes down to preference. Soft gel will be closest to your natural nail. The other systems add more rigidity to the nail and this will affect tone, but again I think that's a matter of preference.
In terms of durability, it depends on how you play. If you're just plucking, it should not make that much difference since the contact between the string and the nail is mostly going to be with the inner side of the top (distal) edge of the natural nail. Any contact with the artificial nail surface is going to be mostly incidental on the top outer edge and you'll probably be filing that on a daily basis anyway. If you're strumming with the front surface of the nail the artificial material will be in constant contact with the strings. IME, even in this application gel is extremely durable, but others may have different experiences.
I agree with MNClassical. SoftGel is like a miracle, and totally changed my life. It's extremely durable.... and sounds, feels and looks extremely natural. 30 minutes every three weeks at the nailist while I drink cappucino and read my emails, and then I never even think about my nails or worry about other activities until my next visit to the nailist.