Wish I had done my research before purchasing. A few weeks after I bought this my brother bought the Thrustmaster TMX PRO which sells for basically the same price as this or less. After using his wheel I would definitely have bought that.
Both wheels do not come with a shifter and both do have the clutch pedal and conical brake mod for more realistic braking feel. Yet on the TMX PRO the mod is easily installed or removed depending on your preference. On the Logitech it is permanently installed and requires invasive action to remove which also voids the warranty. I like it though, it was a little too stiff at first but after about 30 hours of racing it has broken in and feels great.
Both wheels offer an optional shifter, and the Logitech one offers 4 things over the Thrustmaster's, push down reverse, alot quieter, very short throw, and a much lower price. The Thrustmaster one is over twice the price, but it feels better, is made mostly of metal and is harder to accidentally put in to the wrong gear. The Thrustmaster also has a separate gate plate that is included with it to make it a sequential shifter. This is excellent for rally driving where the paddle shifters can be difficult to use. It is however very squishy in sequential mode not having that nice positive click that a sequential shifter should have. Because of that I would not purchase it if you're mainly looking for a sequential shifter due to its poor feedback. Their are better dedicated options out there.
The pedals on the Logitech are 8 bit giving a total of 256 unique positions. This sounds like a lot, but when running F1 cars where braking needs to be incredibly precise the Thrustmaster 12 bit pedals with 4,096 unique positions are noticeably better. The Logitech pedals do grip the carpet better though and look nicer.
The wheel, the G920 is prettier by far. The all brushed metal construction with leather wrap looks good and feels good in the hand. The Thrustmaster is mostly plastic with some rubber grips at the 10 and 2 'o clock positions. It looks cheap and initially feels cheap too. It is however about a 1/4 inch larger than the Logitech and I like the slight increase in size.
Yet this is where the Thrustmaster runs away with the show for me. When actually driving with it the force feedback is noticeably better, its more precise and less notchy. I can't say it is in a whole other league over the Logitech, but it is better. The cheapness of the plastic wheel is all but forgotten from the excellent precision feel you get from the force feedback.
That being said the Logitech is not without its upsides like better looks and overall build quality. The wheel base does have bolt holes for hard mounting. Which is real nice when using it with a stand. The TMX PRO on the other hand has no mounting holes and its desk clamp sticks down so much it will block your keyboard tray. The Logitech uses dual soft mounts that don't stick down nearly as much allowing access to your keyboard. Both wheel's pedal boxes and optional shifters do have bolt holes for hard mounting.
From what I've read around the net, the TMX pro does have a higher failer rate. So if you are looking for something to last a long time the Logitech would most likely be your better bet. Its dual motor gear force feedback system is antiquated and has been around since the G27 wheel which is why it doesn't feel quite as nice as it could. Yet it is a proven system with many G27 wheels still in use today. I'm just speculating, but I think this may be why Logitech has chosen not to update it, just because it has proven to be so reliable.