I applied there as a CFI about a year and a half ago. They run a very professional operation and hold their CFI's (and all employees) to very high standards. They want their CFIs to be available all the time with minimal "secondary obligations." Meaning that you will most likely not be able to have another job, which was my issue.
I'd recommend it as a place to train. But as always, you're training is only as good as your instructor. There are some books out there on how to choose the right instructor for your training. It's more important than you think.
We fly into 36U (Heber City) periodically. While a great airport for primary training, it is a mountain airport and only has one approach. During the winter, we go into SLC to avoid last minute diverts or getting stuck at departure time. The departure has a hefty climb gradient as well.
The folks at OK3 all seem nice, but as the above posters pointed out - when it's you and the CFI in the plane together is where the quality of training matters.