My 2 bob's worth. I was new to all bikes not having been on one for over 50 years after giving up on my beloved Yammy due to constant nagging by the lovely Jane. I knew nothing of the terminology and hadn't a clue what a bottom bracket was, let alone a crank.
This forum has been helpful to me, but it seems many replies here have been somewhat less than helpful.
As a first timer, I ordered a Sunbear from Whoosh. A front wheel motor with plenty of oomph, street legal but heavy as hell, and skittish on loose surfaces feeling not quite comfortable. I then tried a rear wheel Freego Eagle, street legal and a very comfortable more natural ride but sorely under-powered.
My next attempt was a self-build. I went to my local charity bike shop, Hope to cycle.
They gave me the keys to their back shed, and told me to find a suitable bike as a donor for conversion. I went through hundreds and eventually picked a Specialized Crossroads, circa 1980's which was a very light bike at about 15kg. Whoosh then supplied a mid-drive kit a TSDZ2 which was very easy to fit and I was able to chat to Andy on the 'phone to sort out my queries. I have now had this for three years and 2500 miles and am very satisfied with it. It has the most natural ride of any e-bike I have tried and it suits me best. The throttle is a big bone of contention here on the forums, and although the law is a pretty grey area here I would never ride an e-bike without one. It is a real safety feature for me, as setting off from a standing start especially on an incline, it enables me to start smoothly and safely instead of wobbling all over the road. The torque sensor feels very natural, cadence sensors are more jerky. The torque sensor requires more input from the rider, which suits me as I need the exercise.
Because it is a kit and on an old bike, the law is pretty well weighted with it probably being legal in this instance, but these things have yet to be properly tested in a court of law, but I take my safety seriously after having fallen off an ended up in A&E after hitting a lamp-post at 15mph. (Cat ran out in front of me in a narrow alley).
So that is my journey into e-bikes and I will keep this bike as long as it and I last.
Hope this helps.