Hi Andy, and welcome
Its difficult to say precisely what any one person will prefer, but when you say, 'under 100% my own steam', then I'm afraid you've lost me a bit. Do you mean you want a ridable bike to help you pedal, and that you intend to pedal as well, or do you mean that you only want help for the hills, and that for the rest of the time you want to 'switch off the assistance'?
Note that in most cases, good hill climbers are not fast bikes do to the zone that the motor applies torque through, for example the fastest bike, the Ezee Torq, is regarded as one of the worst on hill whereas the Kalkhoff is a relaively slow bike but probably the best on the hills.
I have a Twist (very similar to the Kalkhoff) and although it will climb any hill I have ever faced with its 'drive-through-gears' method, it will do it slowly.
For your info, I too commute on a 22mile-ish round trip, with some hills, and am currently investigating my next purchase which will either be a Trek-Nano conversion or a Wisper 905.
The Trek is basically a normal bike with a small motor (the Nano) and a small battery (will need recharging each way). With this one you can easily use it as a normal bike, and it will provide a small amount of assistance on hills. Top end on the flat of maybe 14 mph without assistance from you, and you can expect the motor to stall on the hills I would say unless you pedal with it. I tried it up a small hill at prestigne without assistance and it dropped to 8mph and you could feel the motor struggling. Having said that it did come 3rd in the Hill climb event, ahead of all the Kalkhoffs and Wispers (but I think that was the rider after all the bike had 21 gears).
The Wipser 905 can push you along at 19.5 mph on the flat (with its off-road mode). Has a powerful motor and large battery (no recharge needed). It will get you to and from work faster than the Trek, Leaving you to add assistance as much as you wish. The downside is that it is not as good unpowered, only has a few gears, and so cant really be used as a normal bike (you certainly wouldnt consider doing a 10 hour country day out on one).
My dilema is that I want both a fast commute to work, and the ability to 'go out for the day' with my family and not either leave them behind or struggle to keep up. I think though in the end, my commute takes priority (I prob need/want both).
Hope this helps.
John