Took a short drive on 4601 today.
There is a single beep when the rear door is activated, and another when it is opened by the passenger. Just a single beep if opened by the operator. The rear doors are currently timed to stay open for about a second longer than the other buses, though it feels like an eternity longer.
Much like the double-deckers, the parking brake must be activated in order for the kneel and ramp to work. A neat (though useless) feature is the ramp automatically activates the hazard lights when deployment begins and turns them off when stowed.
Similar to the 8100s double-deckers, there is a feature where after the bus is stopped for half a second, a "secondary brake" (someone have a better or actual term?) kicks in. However, unlike the 8100s, this "secondary brake" releases smoothly without the jolting.
The bell chime is the same as the articulated and pre-4440 buses, though the housing looks like the STO's.
The seat behind the bus operator is rock hard, whereas the other seats on the bus have some padding, particularly the co-operative seating area seats, which are also fold-down seats. The co-operative seating area and aisle is actually very open, likely because the backrest of the seats are mounted to the wall.
I also foresee lots of operators banging their knees on the farebox getting out of the seat. The seatbelt buckle is on the left. Otherwise, it's a nice bus for now!