Welcome to coffeesnobs, then!
I dont have heaps of experience with heaps and heaps of single-boiler machines, but it seems to me that, as a general rule, going to a more expensive machine of the same type doesnt really achieve much. You will get much more by training yourself up, getting a better grinder, using better beans and making sure your machine is brewing at the correct pressure.
Part of what you mgiht need to consider is how big the filter baskets are. If the FFX1s baskets are smaller, I would expect to have to extract a smaller volume of coffee. You would also need to check if the X1 was pod-only; you might need to pay extra to get a normal portafilter.
In terms of steaming, the X1 seems to have a built-in froth-aider, which is a big negative in my books. With either of these machines, the trick to getting decent steam will probably be to start steaming before the heating element stops, so that the element is creating more and more steam as you go. That, and to remove the crappy froth aider thing. To work out if the X1 has better steam capacity, I would look at the boiler capacity and the wattage of each machine.
At that price, ask yourself if youre prepared to deal with a machine that is substantially similar, but just looks better. The X1 looks cool, but Id rather step up to a semi-commercial machine. Problem is that these cost significantly more than $500.
Hope that helps,