Maybe “是最好吃的” is slightly more correct? I guess depends on emphasis.

這裡最好吃的是牛肉拉麵

這裡的牛肉拉麵是最好吃的

I feel there should be another 'de' at the end. Here in Beijing at least I hear 好吃的 a lot.

I don't think any English speaker would use the word "ramen" for "lamian", whether or not they knew the words are related. Since they don't look or taste the same and "ramen" in English is already associated with either the Japanese dish or with instant noodles.

An English speaker who knew the Chinese name would say "lamian" and one who didn't would probably say something like "beef noodles" or "beef noodle soup".