Do your own research as far as possible, not concentrating on a particular model or manufacturer, first analyze for the type, as there are many.
Motors, Brushed or Brushless? Brushless is more modern, and is rapidly overtaking Brushed motors. Good torque characteristics.
Geared or not geared motor? Geared are popular, but reading between the lines here and on the web generally, its usually the gears that eventually need service, and not all manufacturers allow that. Reckon greasing every 1 to 2,000 KMS. An easy if dirty job, if allowed.
Hub front, hub rear or mid motors. This is the single most important design part to get right in your research.
Front hub is really great for areas that do not have steep hills, that is exactly what attracted me originally, but only a rear hub was actually (second hand) for sale, and I am now on my second rear hub. Love it!
Both with un-geared motors. I can personally recommend rear hub un-geared motors, they are cheap to purchase, the motor rarely needs attention, as the only moving parts are the outer rotor and the bearings, all low wear items.
Mid motor bikes. These almost always have gears inside (as far as I am aware, but never had one apart!), that need regular attention, if allowed by the manufacturer, you might be allowed to do it yourself. Some mid motor manufacturers will not sell spare parts, not even to a bike shop. You have to send the defective part to the manufacturer for everything - many miss this point when purchasing.
Some mid motor manufacturers use digital communications on the bike between all the expensive bits, if one part goes wrong, or "IT THINKS" that a part has gone wrong, it shuts the bike down completely!
All mid motor bikes have at least one single point of failure, the chain, as ALL the drive power from the motor and the rider, goes through this one link!
When it breaks (wear is high), "shank's pony" is the only way to get home, or phone the wife and get it into a (large) car!
These bikes are on average more expensive at purchase than hub motored bikes, also as some even after purchase, they need a steady amount of cash to keep running well.
Research, research, research, make notes, make comparisons and choose what is best for you personally.
Best of luck.
Andy