I have several SIGS. I own the Sig 250c, 226, 225, & SIG 2340. My first gun was the SIG 2340, in a 40 caliber. I would choose the SIG 2340 if I had to choose again my first gun. I love it, it shoots well, always shoots, can changee calibers and hand grips. To change cailbers between 40 and 357 SIG, you just change barrels on the SP2340. This convesion is very inexpensive. To change calibers on the SP250 is more expensive. The only thing I changed on my original SP2340 were the sights, I use it for home defense, and I went with night sights. One drawback I have with my SP2340 is you have to buy SIG's laser sight, since my model has a special SIG rail. The laser sight was about $300 several years ago, but it works and looks fine.
The SP250c has a standard rail and will accept many models of lasers and lights.
Still I think the SP2340 is the way to go. I will never sell mine.