I think it's understandably hard to get the honest truth on a forum that caters exclusively to the vehicle in question. Having said, that, I think I am pretty honest when it comes to the crossfire. Keep in mind that most people are colored by previous experience. People who are used to driving a Ferrari will likely have a different opinion on the crossfire than people who drive a Ford Pinto.

I can tell you that the crossfire is probably the most reliable sports car you can drive. Why? Because the power and drivetrain are pretty basic for a modern car. There are no exotic mechanicals on this car. For example, I considered a previous generation M3 prior to the crossfire, but decided against it because of the potential for costly valve adjustments.
This car is not cheap. When new it was close to $40k car. It has a mercedes engine. If you are looking for simple and basic transportation, hyundai makes a great car these days. Oil changes at the dealer for this car typically cost $100 or more (they cost over that at my dealer). Tires can get pricey, especially if you want the most modern and popular sticky summer tires. Replacement parts can be pricey if you aren't careful. If you buy something out of warranty you should not take this car back to the chrysler dealer. You need to find a reliable independent technician who knows Mercedes cars. In reality, this car should be no more expensive to maintain than any other car that you can buy for the same money when it was new.

In relation to what? Go to any chrysler dealer that sold these cars and ask the service people what they think. They will likely tell you that they are among the most reliable cars that come through the doors. Being that the crossfire is german, you may get some occassional problems with sensors, but all the important parts--engine internals and tranny are pretty solid.
Again, what does this mean? Go to tirerack.com and price out tires for the crossfire. You will get your answer in 5 minutes with regard to tires. Part. If you buy them from the chrysler dealer they can get pricey. Having owned VWs most of my life, I have learned to get parts from several online venders that specialize in european cars. This can save big bucks.
Another subjective measure. Track times do not equal handling. But neither does tire grip. The crossfire has a ton of grip because the tires are so huge. BUt the car lacks a certain feel that you get from more established cars. There is very little steering feel--thank you mercedes! Taking turns quickly I notice that the car isn't terribly stable and can feel the car squirm a bit, like the bushings are way too soft. It's not terribly, but if handling is a major consideration for you, this may not be the best option. Dynamically, the Z4 coupe and porsche boxster give much more feedback and are more stable when driving in the twisties.
I think you can do the math here. Premium isn't all that much more on a per tank basis than regular. But, for the size of the car and output of the engine, mileage is pretty poor. My old GTI which weighed about the same and had 200 hp easily got 30 mpg.
YOu must be hanging out with Chevy or Ford guys! Besides, the crossfire really isn't a chrysler.
Downgraded is inaccurate. Outdated would be correct.
It all depends on what you're looking for. I love, LOVE, the Z, but the interior is terrible. The miata? The crossfire is much better place to spend time, though the miata is likely a bit more fun to drive. And many of those other cars you listed don't even compete with the crossfire. Look, the crossfire is best thought of as a 2-door, 2 seat C class mercedes with the sport package. The car was more of a very high quality design exercise. It was never designed to be a maximum performance package. It's just not. Much like the original SLK 320 wasn't about maximum performance. This is a car for people who like interesting vehicles. If you want to be johnny speedracer, there are many better cars out there. If you appreciate details and what I consider a high level of build quality in a car with only 2 seats, then the crossfire is a great car. It's probably the most friendly 2 seat sports car for daily driving.