New Vios G Oct 07: pickup good, stable, and no major problem. Belting problem (squeeking) on cold start, rectified/fixed on 3rd service. Now all quiet. I heard the belting problem for Vios is quite common. Feels empty, simple, spacious, rougher/coarser, but nice to touch.
City VTEC March 08: pickup linear, stable, builtin antenna (pre Nov07 is not), updated TCU - engine break now stronger, suspension harder than new Vios and also previous City VTEC (pre Nov07). So far engine more quieter than new Vios. Cannot play MP3, stock ICE is not as good as Vios, a little stuffed (lesser space) compare to new Vios and also lesser compartment/pocket to put things vs Vios. Feels like more attention to detail, more delicate, more refinement but not nice to touch.
As for the 'auto' lock of City, this is Cobra alarm system, with speed >=20kmph it will lock the door for forgetful driver safety - the driver should lock the car him/herself. Almost all Honda & Toyota cars are like that.

Unlike el-cheapo alarm that just lock the door when you press the brake pedal hard - even you traveled to 100kmph and never press brake before, the door is still not lock. Learn to lock your car when everyone is on board before starting the car.
As for major problem, usually are isolated cases.