Clarifications. You can't tell, from the looks, if a game runs on OpenGL or DirectX. Example video.
http://www.youtube.com/watch?v=HC3JGG6xHN8 So when X-Plane looks different to FSX this doesn't arise from the API in use but mostly from the different artwork and approach made by the developers, not being the ACES team. Here's a XP dev on the details.
http://developer.x-plane.com/2009/11/directx-opengl-and-x-plane/You can surely compare every sim with another one. And that's what we do.
Ahmet's question on the now current XP 10.20 x64 build is a good one. It offers, after a beta phase, a 64 environment and therefore allows some limitations to fade out. Means that situations like 'Your computer has run out of available memory' can still happen, but not at the nowadays low limits like with FSX and P3D. Now this isn't a problem when running the sim at low settings or without a combination of dense and highly detailed addons of course. But the other way around it will become a problem when you are not limited by achievable fps but, later, by a sim running out of usable memory. Combine nice airliner addons and a lot of scenery and you may well see the dreaded 'oom' message. Bummer!
My personal experience with X-Plane is rather positive although it features some downsides like lack of seasonal textures and the huge quality spread among the default planes. Some are very nice and interesting, some others are coming from way older versions of the sim and lack of optics and 'real' feel. Same as with FSX nowadays, it's recommended to get a decent freeware or payware plane to check if the characteristics suit you.
I'd say that the flight model in XP
might allow for a more lively feel and also seems to offer a bit of detail when it comes to weather influences. That's different than the FSX feel (mostly with small planes) where you either fly on rails or get totally thrown around because the turbulence got wonky. Best would be somewhere in the middle, right? Well, as said, this all still depends on how much work the plane dev has put into the flight model details. So there are bad planes in XP, same as there are in FSX.
A general advantage of one sim over the other isn't present in my eyes. You can render fairly good planes with the table based approach of FSX and you can also achieve this with the blade element tech of XP. I could see an advantage for XP when leaving the normal flight envelope. So, for smaller planes and some artistic targets, this
could come in handy. With airliners, it may not matter a bit or even form up a downside.
Graphics? Well, if you run a modern graphics card in XP, you
will benefit a lot. The more the merrier.
Means native HDR and a pretty high GPU usage can come together. The CPU isn't used that much. Older ones may still be fine. Also, the nights in XP are just amazing. As a tip, the cloud detail is a major factor in XP. Small cards will need low settings in heavy weather while you can crank that one up with e.g. a GTX680.
Downsides. In a default XP, certainly the ATC and the AI traffic. That stuff is weird.
Menus, tweaking and calibration. Well, the menus look different, but since the average FSX/P3D user already is a tweak and fiddle guy by design
, they shouldn't cause too much confusion. I did not have to tweak a single cfg file yet and I got my joystick, pedals and throttle running in a few minutes. Same for TrackIR.
The default scenery offers some highlights on the autogen (if one can call it like that) and the roads and villages look a bit more alive. Sort of like zooming in on Sim City if you like. I would love to see more variations though and I also think that the 'smart' road placements overshoots at times. Well, it's default and I'm comparing it to my addon loaded FSX, so keep that in mind.
Stability. I have yet to see any trouble with XP. The fps can be tuned with the default menus and the rest like the resource management is automated. So I never saw memory trouble so far although I did get some of the new '64bit recommended' addons.
So what would be the best way to test? I'd say you should grab the current demo (it should update itself via the tools to 10.20, check that!) and perhaps test some of the default planes and the demo scenery around Seattle. Crank up the details, add clouds and fly at night. The latter is the best part and if you have enabled the road traffic, it will be great.
I think that you can add planes to the demo. So perhaps surf to some freeware sites and look for the comments about a decent flight model. You may then adjust the control sliders in XP to achieve the feel you want. Remember that you may have learned some things the wrong way from FSX. Habits. Not too uncommon among us 'old' sim folks
and we may easily trick ourselves into thinking that wrong is right, if you know what I mean. Just referring to the known FSX flight model downsides we may have gotten used to.
I wouldn't be surprised if the first XP impression is
not good. The thing had to grow on me and from being a FSX 'adjusted' fellow, this seems logical at first. So give it some time and keep in mind that supporting those folks gives money to a small company still keeping the flight sim spirit alive against all odds and with
really new instead of rewarmed stuff.