Motion aspects

Motion aspects of the real 737 simulator:

there is a mix of lateral (sideways) and roll tilt during taxi. I found the taxi motion in some cases not completely convincing. Actually I felt a bit nauseous during the taxiing to the runway. This seems a common side effect in simulators.
Wind gusts are very clearly felt, even when the plane is at standstill, mainly by lateral motion.

The tilt to simulate the acceleration is considerable: I estimate about 40~45 degrees. Books are sliding backwards. This gives a really great feeling of acceleration.  I realize now that the tilt in my homebuild motion sim (20 degrees) is far to little to mimic these kind of accelerations. There seems to be little washout in the takeoff acceleration. 
The lateral  linear motion is also considerable when making rudder corrections. Very convincing. Especially during engine failure simulation, the lateral force is  strong enough to push you from your seat if you're not holding on to something.
Heave on the runway (wheel vibration, gear suspension) was very little; much less than I would expect. (maybe the runways at Schiphol airport are very flat) There is not much vibration in the simulator. O r maybe I'm overdoing things at home.
Rotation feels good, with some heave and backpressure feeling, but not a  lot. There is no gear buffeting vibration. Gear rumble sound is quite well done, but lacking the low frequency, so no gear retraction rumble or clunks like FS. Same with flaps retraction. I may be off a little, as the instructor had turned the sound down for easier discussion. 

This was quite like real, with small lateral movements, but since the weather was set calm (mostly misty CAT III) there was not much turbulence action anyway. The rotating feeling during turns was very little, but therefore also no false cues when going back to level flight. 

 Deceleration when extending flaps was very realistic, again due to the large tilt angle possibilities.

The flare feels OK, but I would have expected a bit more heave. Touch-down is big heave jolt simulating the gear suspension, but missing the multiple wheel touchdown feeling in real landings. We made some rough landings, due to severe conditions (like single engine + crosswind + CAT III) with considerable rudder action. This lateral motion during touchdown and steering on the runway feels really convincing.
Note that the motion system also has it's limits: At some touchdowns I saw some warning lights and once we had a control loading and motion system shutdown.
The heavy deceleration during braking is very convincing with the large tilt angle. Releasing brakes motion is quite good. They seem to do something smart here, as I did not feel the "rotation back to center" feeling at all.      

Overall motion feeling: The system seems simulate low frequency forces, no quick shudders or vibration. I judge the frequency bandwidth to roll off at 1Hz or or less, very different from my home-build system 7Hz roll-off point. On the other hand the motion is very smooth, and I did not feel any sudden actuator limiting. Lateral is indeed a very important motion cue. Also important is the large tilt angle for acceleration/deceleration. Heave action was less than expected, I did not really feel my stomach, even during some go-around maneuvers where considerable sudden pitch-down was required to overcome the trim setting.
Overall, the 6doF system is pretty awesome compared to my low cost 3doF system. Lateral motion will definitely be on my "next thing to add" wish list, although I have yet to figure out a smart way to do this.