Ideal for me? Well... I like the 3" GP-100 for a home defense gun. Other than that, neither the GP-100 or SP-101 is "ideal" for me for a concealed carry piece. I carry a S&W 442/642. I think the SP-101 is still too large for comfortable concealed carry unless you are carrying the gun like a cop. But many like the SP-101.
For walks in the woods, I carry a 22 in most cases, a 4" 41 mag, or the 3" GP-100. A 4" GP-100 would be a very good choice for this purpose for most people in the lower 48 states.
You have not defined your reason for choosing one over the other where size comes into play.