Please see my reply to the OP over in the Clarity Fuel Cell forum. I've been very pleased with the range of my 2017 Clarity Fuel Cell. I've taken two trips on the Coast Highway, and found the car easily covered the 300 mile distance between the Santa Barbara and Campbell stations, traveling via Santa Cruz, Carmel, Big Sur, Cambria and San Marcos Pass to Santa Barbara. Similarly, travelling between Northern and Southern California requires only one refueling stop, at Harris Ranch. I recently drove from Orange County to Sacramento on I-5, topping up in San Juan Capistrano and refueling at Harris Ranch, arriving in Sacramento with over 100 miles of estimated range remaining.
I generally obey the speed limit, which may explain why my range tends to be close to the advertised number.
As to cost of fuel, the arithmetic points to the $15,000 fuel allowance being enough to cover 59,000 miles, and the mileage allowance on the lease is 60,000, so the risk of having to shell out for fuel seems low. At $16.54/kg, the $15,000 will buy you 907 kg. At 65 miles/kg, that's 58,955 miles. At least I think that's right. Math isn't one of my strengths.
2017 Honda Clarity Fuel Cell, Black Crystal
2018 Chevrolet Volt Premier, Green Mist
2010 Toyota Prius II, Pearl White (currently in New York with my daughter for college)