MagLev is not a smooth ride
No, the Shanghai Maglev is not smooth, or quiet: I was surprised. The ride is similar to a suburban bus on Sydney's goat-tracks: an undulation in the track at 60 km/hr becomes quite a bump if you hit it at 430 kph (but you jet drivers would know all about that!)
I was also surprised that there was quite a loud whine penetrating the cabin: I presume those electric bits are working very hard indeed.
Compared to the Japanese Shinkansen, the Guangdong to Wuhan HSE, the French TGV or the German ICE (yeah, I love trains...) the Maglev is substantially rougher and noisier. The ICE and the Shinkansen in particular are glass-smooth. I remember pulling out of Tokyo listening to the soporific "knock knock, knock knock" of the rails and thinking "Isn't this thing ever going to get moving? We must be still in the shunting yards." Then I looked at the speedo on the wall at the end of the carriage: it was climbing steadily through 180 km/hr! Those rail-joins, I discovered, are 3 km apart :-)
Compared to a jet aircraft, the MagLev is a bit like a run in an A330 from Singapore to Sydney, across the bumpy bit just south of Singapore, but a little noisier.
Hope this helps