My previous motor, a 320D E90 M-Sport 59 reg had Servotronic Steering which I thought at the time was pretty good.
All in all an improvement on my previous to that E90 with hyd steering, 55 reg motor. Why? The E90 with SS was a doodle to park and the steering stiffened up a nicely at speed with reduced angular movement. Very Nice!
My current F30 with 2VL Variable Sport Steering is even better!
Switching from Comfort to Sport is quite noticeable, giving the car a stability and confidence in cornering, which compared with all other cars I have ever driven is the best by a long way (bar E90).
My bench mark in a cars ability in stability and cornering is to take at speed a long sweeping motorway curve, overtaking in the wet thro' the spray.
My F30 320D does this with complete confidence, the E90 comes close, in holding the road with accurate positive steering, with stability and road grip.
Don't forget, the F30 series up to M-Sport is designed as a comfortable family saloon car, not an M3 type with leanings to track days and boy racers!