The P-345 isn't really any better, (with exception of the lighter trigger) just different. The grip angle and size are way different as is the weight. The internal parts have changed considerably. The barrel lock-up and recoil buffer spring have been redesigned.
The P-345 also has a magazine disconnector, a loaded chamber indicator, and a key lock. Also, the P-345 has a manual safety and is not available in a decocker only because of California requirements.
I bought a P-345 a couple months ago and found it to be a very nice gun. I can't really say it's better than a P-90 though.
