V1 is approximately on par with 9500ix overall performance wise when you average out the sources, possibly a little bit better (arguably) and has arrows to help you determine where the cop is. Also has a strong rear facing sensor I believe.
As I’ve said, I’ve had both, arrows are very useful and are not just a gimmick, however with that said the GPS is seemingly more practical for a daily vehicle as I’ve described above.
I’ve never heard of one melting and left mine inside no problem.
V1 updates are essentially you gotta buy the new one if you want the update. It costs around ~$200 to upgrade and they just send you a new one. Meanwhile you can sell the old one with ~$100 loss on ebay and buy a new one if you really wanted. Both have very high resale.