I haven't tried the P30, but it is on my list of "want to's".
I used to own a P229 in .40.
I didn't like it, it always felt like it was going to squirt out of the top of my hand. Too "fat" at the top of the grip.
I never had any problems with it, but it was a fairly large sized gun and heavier than the G19 that I use today.
This was in the late 1990's though, the only experience that I have with Sig's current quality level is a friends P226 that shot something like 8" low and 3 or 4 to the right out of the box. We were shooting at 8.5 X11" sheets of paper and almost never figured out where the rounds were going... I finally noticed if I aimed over the paper I clipped the bottom right of the target. We even had my brother who has a nearly identical Blackwater Edition shoot it and he couldn't hit the paper at all. The look on his face was hilarious. Especially when I was getting hits and he wasn't and I don't shoot Sigs as good as he does.
He called Sig and they told him to try different ammo.
He sent it back and they fixed it. I haven't shot it since then, so I assume it is better now.