Hi John
The Yamaha was the bike of choice just before the Lafree was introduced, but the Lafree Twist's lighter weight and more bicycle like characteristics won the day.
The Yamaha was a fine e-bike though, the only criticism of it from some was that it was more autocycle (moped) than bicycle, and A to B felt that also. As with the Lafree, there was a widespread expression of disappointment when Yamaha discontinued in in the UK due to poor sales.
So no, you haven't bought a pig in the poke, any more than with any other discontinued product, and it's much better than most. Batteries are the key thing, and you've clearly made a wise decision in that respect. Only spares might just be a problem, but there's a Yamaha specialist in the south here who offers spares and service on them, illustrating the range on the website:
Electric Bike Centre
I think the Ego is a good prospect too, wish I had the space for one.
All I'd add to this is, enjoy your bike.
.