Safari Park is my favorite half marathon, if I had to choose only 1 half to do each year, this is the one I would choose.
To start off, the profit from the race goes directly toward a cause, i.e. new habitat for the Tigers or the Rhinos.
Also, a fun factor of this race: the organizers allow you to vote on the T-shirt design AND the medal design. The choices are always so well-designed. Good swag always makes a race more desirable.
The course is challenging, but only moderately so. There are 2 HARD hills, but the rest of the course is comfortably rolling. The scenery throughout the entire race is beautiful, and the support and entertainment is pretty good. From milking cows out for petting, to a camel photo op, to fun stomp-like drummers, to a very high energy MC Hammer look-a-like.
I highly recommend this race, but the hills are not for sissies!