The choice between crank and hub motors very much depends on the type of riding you are considering.
We make and market both centre and hub motored bikes.
In our experience, off road cycling where you will encounter very steep sharp hills is better with a good centre motor such as Shimano or Bosch, they may look ugly to some but the power from the motor goes through the gear system, this may not be quite as efficient as a hub drive but on very steep inclines they perform well. Perfect for mountain bikes.
Around town and for country rides in areas without extremely steep hills, the more obvious choice is a hub motor, they are neater, more efficient and don't put any extra wear and tear on the chain and gears so they will last longer. Being situated behind the rider hub powered bikes are quieter and with the latest motors being so small they sit neatly and unobtrusively behind the gear cassette, they are easier to service and normally less expensive.
As the guys at Rutland say it is important to test a few bikes and motors before you buy, whether it's a hub or centre motored bike a torque sensor and good controller make all the difference. The bike will be all but silent and feel smooth and natural without the need to pedal for half a turn or so before the power kicks in, very important on hill starts.
Companies like Bosch have done a superb marketing job on centre motors but don't believe all the hype. In my opinion hub motors are better in most normal day to day conditions, but cannot compare with a centre motor for mountain biking or very steep hills.
I hope this helps.
All the best, David