The much higher highway efficiency of the Ioniq narrows the travel range: 151 miles for the LEAF and 124 miles for the Ioniq.
When new anyway. IIRC the Ioniq has a poor TMS and we know the LEAF does not have one at all.
Tough choice between two bad choices. If those were the only two cars in the EV universe I would choose the Ioniq if the range was adequate for my driving patterns but if at all possible I would wait for the Tesla Model 3 SR or consider a cheap Bolt. Spending $20k - $30k on a car with a poor battery is penny wise and pound foolish.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
2018 Tesla Model 3 LR, Delivered 6/2018