Hi John,
I'm in the UK too, and I bought my Magic Pie
(direct from GM in China) when they were first launched on 20
th October 2009, but unfortunately it took a while to arrive due to the large demand.
I had to modify my hub
(see this post for more details) to allow correct centring of the rim, so that I could use wider tyres on my bike. But as a direct result of this, GM quickly altered the design of the original hub to allow the rim to be centred
(and the excessive spoke angle has also been sorted). So if you buy a Magic Pie now, you should not have any problem with the centring.
I have been using my modified Pie over the last six months without any problems whatsoever, apart from the dog struggling to keep up on occasions.
The rebuilt wheel continues to runs true, and the spokes
(which have not been touched since the rebuild) are still nice and tight.
I use Lithium Polymer battery packs, but I will not recommend them, only because of the possible danger of explosion with these batteries if they are abused too much. If you are fully aware of the risks, know what you're doing, and are ably to closely monitor the charging process each time, then I see no reason why they should not be used.
The GM battery packs are considerably safer than
LiPo packs and are perfect for use with the Pie.
On a 25.9 Volt
LiPo pack
(29.4 Volt max), my 26" Pie has a top speed of around 15mph, which is just about right for the maximum speed allowable under the current UK Laws.
On a 51.8 Volt
LiPo pack
(58.8 Volt max), my 26" Pie has a top speed of around 25mph, unfortunately this is too high to be legal in the UK, so it's for off road use only.
I would expect GM's 24V and 48V Batteries to give similar top speeds to what I get with my
LiPo packs.
I didn't like the way the pedelec function works because there is no control over the throttle while pedalling and the assistance can be too much at times, so I have since removed the pedelec unit.
The regenerative braking is very effective for stopping quickly, but can be too much if you just want to slow down slightly. This means that the brakes need to be released and reapplied on a regular basis on longer inclines. Variable regen would completely solve this annoying problem, but unfortunately there is no sign of it being included just yet.
The large diameter of the Magic Pie combined with the additional magnets/poles produces very good torque, which makes it ideal for hill climbing or for pulling additional weight. Unfortunately there is a downside, there is also an increase in the resistance to pedalling when the motor is not being used. If you plan on doing a lot of riding without the assistance of the motor, the drag of the motor
(and the additional weight of the motor and battery pack etc.) will require far more effort to maintain higher speeds.
The geared minihubs have a freewheel device to eliminate unwanted motor drag when not being used and are a lot lighter too, but they cannot be used for regenerative braking and are not as powerful or as fast as the Magic Pie.
I find the cruise control feature very useful when walking the dog or cycling with other cyclists, as it allows me to set a constant speed to match their pace.
Apart from the aforementioned centring problem, I am very satisfied with my purchase, and impressed with its hill climbing capabilities.
Alan 
