I have test driven every EV available. The Leaf feels higher quality inside. It's a better "car" than the Bolt. It also has more tech features.
However ...the Bolt is a better EV. The lack of thermal battery management in the Leaf will destroy the battery in anything but perfect climates. If you are leasing for 3 years, then yes you might want the Leaf +, so long as you don't go on long trips (charging speed is crippled with fast charging due to overheating). You will be getting rid of it by the time the battery is going out.
If you plan to keep it long term, or do road trips, get the Bolt. GMs EV tech is ahead of Nissan's. Look at 2011 Volts vs 2011 Leafs. All the leafs with original batteries will have degraded to the point where the car can't be driven anywhere. The Volts will show very little drop in range because of the conservative charge management and thermal regulation.
TLDR, Leaf+ is fine for a lease, get the Bolt if you plan to keep it 3+ years.