could somebody please explain the advantage and disadvantages of a front or rear hub motor
There are variable elements of truth in the previous responses but as you have asked specifically about hub motors, my experience of two current EAPCs, one rear-driven, the other front-driven, is that there is little to choose between them in leisure cycling on road, towpath, light off-road track and occasional diversions over rougher terrain unkind to any type of bicycle.
My rear-hub motor is more powerful than the front-hub model I ride but both serve their purpose very well, indeed almost equally well on account of a large weight advantage in favour of the lesser-powered model. If the more powerful motor were transplanted to the front wheel, I'm sure the bike would become a little unwieldy at times but in its rear-wheel application, it suits that bike very well. As for spokes breaking, unless you happen to have a badly built wheel, you will probably never encounter that problem with any legally permitted power found on an EAPC from a major player in the UK market.
Neither of the two bikes I mention is equipped with internal gears which I happen to like though they seem better matched to non-sporty, Dutch-style bikes used solely for easy leisure riding.
Generally, front wheels are easier to remove for puncture repair but with the right tyres, that problem is considerably obviated. Having said that, it's not always necessary to remove the wheel for puncture repairs and for my own peace of mind, I did two things when I bought my rear-hub driven bike:
1) I removed the Continental tyres and fitted Schwalbe MPs.
2) I did a couple of dry runs in my back garden to ensure I was au fait with rear wheel removal and had the ability to disconnect the main power connection, essential to the task. I always carry the right tools to ensure I can perform that job out in the sticks although I replace the tube and leave inner tube repair till back at base.
In summary, I would not disregard any EAPC on account of motor position alone. My personal favourite is the centrally driven motor although any silent drive is good in my book as I dislike the noise that emanates from many geared motors.
Tom