Even if you do most of your riding in socal, I wouldn't buy outerwear with less than 10K ratings like the first one you posted. You may hit other spots around the country or get caught in a little weather. Also, both of those jackets only have critically taped seams.
That said, one of my most used jacket is only 8K rated and has critically taped seams and is great for most socal conditions, but if this is going to be your only jacket, you may want to look at something with some better specs just to give it a wider range of use.
Evo | 390 | Kaiju