I think I would find the barrel moving back and forth during firing the most disconcerting thing... complex internals would be a pain... but with proper training and practise you could probably get used to almost anything.
The underbarrel grenade launcher is attached to the lower stock and doesn't move with the barrel as it recoils, but the bayonet is attached to the barrel... I wonder what effect the extra weight would have on the rate of fire.
Of course there is evil genius in the design for close combat... stab them in the chest with your bayonet and then fire a burst of 4-5 rounds would have the barrel and bayonet jabbing in and out of the guys chest in addition to 4-5 rounds hitting him at point blank range... nasty
I would think for a police officer that the two round burst would be very useful as they are often trained to "double tap" with pistol rounds as two hits is likely to bring down a fellon faster than a single hit... this weapon has a built in double tap option and in police type situations they could deal with the added complexity of the weapon and spend the extra time maintaining it.
Of course not many modern weapons have pulleys and cables as part of their design... just off the top of my head the only other weapons that have such things are 30mm AGLs and 12.7mm HMGs for loading that first round with a very heavy recoil spring.
In terms of ergonomics and ease of use however it is not totally awful.. it has a western style peep iron sight and the controls are located closer to where you can reach them easily.
The magazine does stick out at a strange angle, but unlike the standard AK you can fit the bayonet and the underbarrel grenade launcher at the same time while still being able to use both.
The muzzle brake of the AN-94 is interesting and I wouldn't mind testing it... I have the AK-74 type muzzle attachment for my chinese AKM and I also have the model fitted to the AKS-74U and of course the AKM muzzle brake, though I prefer to use a suppressor.
I have a locally made suppressor, but would love to get my hands on an original Soviet model, though I hear they have rubber "wipes" in them that need to be replaced after 10-20 shots have been fired which sounds like a bit of a pain.