I love my V1. I also have an 8500 x50 and I can honestly say the v1 outperforms it in just about every way possible. The v1 seems a lot more sensitive than my x50 ever was. The v1 picks up instant on when the cars in front of me are hit....my x50 never did that, it only picked it up when I was being hit. The v1 also seems more sensitive when going over hills and around corners. The straight-line performance is also pretty amazing as well. It's all useless without common sense though. If you're going 10 over, you'll more than likely have enough warning to get slowed down, but when you start going 20-30-40 over, then you'll probably get busted.
There are some situations when a detector won't help at all. If you're the only car on the road, and a cop comes around a corner, hits you with instant-on, you're pretty much screwed. I had this happen to me a few weeks ago, I was going about 10 over, got hit with instant on and saw him turn around. I just got a warning out of it though //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif.
As far as the 9500i goes, I wouldn't buy it just yet. IIRC, it has some problems. It has the ability to block alerts in certain areas...while that's great for door openers, etc, it also blocks out potential police radar threats. I also remember reading that there isn't really a way to take full advantage of the GPS yet, because Escort has not released any updates that would allow you to set locations for speed cameras, stoplight cameras, etc.
You can't go wrong with either detector (v1, x50, rx65), but if I had to choose, especially after using the V1 and the X50, the v1 wins hands down.