Handle is comfortable. Proud liners are crowned and polished along the exposed edges.
I haven't tried the GB1 myself, but I really like the GB2's handle design. I call it grip-agnostic (quite un-Spyderco in that regard). The s-curve spine rides your thenar eminence just so. The finger choil is light and accepts anything you brace against it with (forefinger, middle finger, thumb). I wouldn't thrust-stab with this, but it would be way worse on the GB1.
If you're familiar with Benchmade's Griptilian, 940 handles, you'll have a good idea how this feels.
Hole size is not really a problem unless you prefer to stick your whole thumb in it. All you need is purchase along the top edge.