Both - and ideally in the same girl! But that doesn't always happen, as we well know.
I have a regular I go and see, and she's not the best looking. Not ugly, but not a model either. However, she's great fun, always have a great time with her, she does my likes, treats me well, is excellent VFM, and I enjoy it, despite not being bowled sideways by stunning beauty.
On the other hand, I also punt girls that are great looking, but not as great in performance as the previously mentioned. That's not to say they are bad at all; so far I've been lucky and only had a couple of shit/not good punts - one was gorgeous, but so lack lustre in performance, and obviously I never went back to her. The other was so-so looking, and so-so performance, so I didn't go back to her either. The prettier girls I've punted with have been perfectly acceptable in performance, and I've enjoyed my time with them also; no regrets.
So sometimes if you can't get the complete package, you have to go down different avenues. Put it like cars - if you can have fast and fun, but shit MPG, you can live with it, even if it's not the cheapest to run. If you get great MPG, but it's not fast, but still acceptable to run, you can live with it. But if it's slow, boring, shit MPG and costs a lot to run, why would you?
But trust me, if I could find a WG that ticks all the boxes of the performance and enthusiasm my regular gives, coupled with a combination of her likes/will do's and the likes/will do's of a few other WG's I've seen, and have that girl have the looks of the prettier, young, super sexy WG's I've punted with, and be local, and great VFM/rates, I'd be a very poor, very tired, but VERY happy man