wizbang

BMCL
Light frame but with spot for internal soft weights
Completed unit is trim neutral
Electronic controller as well as KISS valve.
Offboard system as standard capable of breathing off at depth and feeds the BOV.
HUD
Frame capable of various tanks.
4 to 6 hour scrubber duration under worst load.
No tools required for cleaning breakdown and calibration.
Sensors are easily purchased (various brands types usable in a pinch)
Sensor connector is corrosion proof.
Place for a forth cell as std
Solenoid is servicable
A simple way to drain the system from a partial flood
Batteries are std, cheap and readily available
External on off switch, reachable during the dive
Set points can be changed and adjusted during the dive.

and maybe
When the controller is switched off the handset can still display the PPO2

that should do for now I am sure other will list some stuff that I consider a must have as well.