First, you need to decide if you still want to be a true cyclist when you own an ebike or you simply want an electric motorbike. What's important and I found out the hard way is that, when you stop pedaling on a custom or properly fit bike, your aches and pain that you don't get with the same bike suddenly will appear. You no longer have the pedaling forces to keep your body in equilibrium to the whole bike. Case in point is with my Dahon Mu SL. It's a super comfy bike when I pedal with motor assist at 95rpm cadence. But one day when the stupid Sun Race freewheel broke (literally cracked and it freewheeled all the way), I had to engage the throttle option of my Bionx system and the ride home was tiring and aching as I feel every single bump along the way.
If you simply want a powerful motor that can go fast and for longer distances without you pedaling or just occasionally so, you need to choose a bike that is upright and equipped with every vibration and shock absorbing devices (front shocks), gel seats with a suspension seatpost. Saddle won't work if you don't pedal that much. You emulate basically a motorbike setup. And that's it.. Think about your MTB setup and you will get what I mean. Your steel touring and Seven Ti are designed for real riding. If you plan to continue enjoying these bikes, you need to plan to ride them period, albeit with a motor installed.
By the way, The throttle option on any of these systems, except Bionx, gives you either on/off or semi proportional but not anywhere close to the real proportional finesse of the Bionx system. The proportional power of the Bionx system works with your bicycle gears to give you levels of assist within 1 assist group too (you have 4 levels)! Let's say you want to pedal at 95rpm on the flats and up the hill, you can switch your gearing to maintain same cadence while maintaing the same assist level, hence same speed! The assist level bar graph of the Bionx console will tell you if you're relying too much on the motor power. I've determined that as long as I keep the assist level to about 3 to 4 bars, this has an effect of saving on battery power, because it allows you to contribute some of your pedaling power or less of yours to the total power output for forward propulsion. Basically, your shifters can act as your power output selector or cruise control. If you run a set of Campagnolo or Shimano brifters or bar end shifters, the Bionx is superb.
No system so far has a strain gauge like the Bionx system that can measure your total cycling power output, which is the beauty of the whole system.. Just last weekend, I with my Dahon went out with my riding friends on regular bikes for a total of 65km (with 7 hills, one is an 8% grade), averaged 27km/h and at the end of it all, I still had 3 bars left, going to 2. I was still fresh at the end of the ride -- I can't say the same for the others though. And my system isn't a Lithium based system. It's 24V NiMH, the basic model! Just imagine if I have the Lithium option -- eyes rolling!!
If you plan to ride your bike with the motor assist, then you need to plan on equipping the motor system to the lightest weight bike possible. That was why I chose my Dahon Mu SL and kept my Trek carbon race bike as it is with a 17lbs Bionx system. Weight has no bearing riding on the flats, but it does when you climb hills. It's bearable climbing a 36lbs bike with motor up any hills, not so if you've got 20AH batts with a heavy 5 series Crystallite system and a heavy mountain bike with shocks. Hell, I've toured 8000 miles with my Bike Friday New World Tourist in Montana, Wyoming, Idaho, Oregon and Washingston and had climbed any imaginable and steepest hills loaded with camping gear, so 36lbs is nothing if your battery suddenly conks out on you. The Bionx motor does freewheel somewhat, but there is a slight noticeable resistance, the same resistance you get when you turn on a German made Schmidt Dynamo front hub with the light on. I have that on my touring bike btw.
The downside of the Bionx kit system is that, it is expensive relative to other systems, but it really isn't because it comes with a watts meter. A Cycle Ops Power Tap rear bicycle wheel can cost as much as $900 too! Secondly, it is not as powerful watts/price as to the other available systems out there and is not a great as a power on demand. Other systems can go up to 72v, but that's bordering on riding a motor bike rather than a bike. Besides, cars will have a tough time judging you because they can't understand why you can match their speeds when you're on a bike hardly pedaling.
As you would have probably noticed by now, I do ride with a Bionx system and I love it very much. For my purpose, it's clearly superior to anything out there in a view of a cyclist. And I've met other cyclists with Bionx systems installed and they all have exactly the same requirements as I did, that is ride the ebike like a real bike. Choose the Bionx system if this is what you want, otherwise the other systems will do well for you but on a mountain bike with shocks.
