I've got a g25, but I use mouse + pedals. (Use the wheel for ps3 and other games though)
For the simple reason that my table is too wobbly, the wheel is too noisy, takes up too much place and because I'm used to steering with mouse.
In slow cars I am as fast with wheel as I am with mouse. Faster cars I prefer mouse because i can react quicker.
Imo mouse isn't more precise than wheel, it's just faster (lock-to-lock).
So you can react to oversteer/understeer a bit quicker maybe.
It kinda compensates for the lack of FFB
You can achieve the same by setting the degrees on ur wheel very low though.
And lol @ the endurance argument:I couldnt do longer than 2hour stints back when I didnt have my pedals yet. You try to hold your mouse for that long, without releasing it even for half a second (except when your doing a pitstop) and for more than 90% of that time, holding or tapping your left mouse button.
It kills your wrist and fingers, trust me