I own both the P2398 and the P938. I had some growing pains with the 238, but after Sig went to the flat recoil spring and the V3 magazine, the problems went away and the P238 was my primary carry. I always wanted the heavier caliber, though, and recently bought a P938. The first 3 mags through, I had a few FTEs, which I attributed to the pistol being very stiff. I have put over 100 rounds through since with no malfunctions whatsoever, including Winchester White Box 115gr, Remington Golden Sabre, Hornaday Critical Defense, and my new carry ammo, DRT (the frangible stuff, 85 gr). Recoil with the DRT in the 938 and my Kimber Solo both is noticeably lighter than the 115/124 gr ammo.
My only knock on the Solo is that I would like the grips a bit thicker, but I have some G10s coming to fix that problem.
Sig seems to have learned from the problems of the 238, and now both the 238 and 938 are great pistols.