I always take Hertz points because its the main way to get them. Airline miles can be earned a thousand different ways and if you need a one-way rental they can be worth $.25 -.50 per mile. So, you are effectively getting 20-50% return on dollar spent (even more with bonus promos). Hertz points are based on spend, but sometimes they have bonus point promotions that quickly add up. Do google search before you book to look for these promos. Example they ran a 100 mile per day bonus last year I spent ~$900 dollars over 90 period and received ~10000 Hertz points which I used in Europe for 3 free weeks of Green collection for $1800 worth of rentals.^