[subject] + 堪称 + [noun]
[subject] + 堪称 + 一流 / 经典 / 完美
堪称 says the subject has earned a title of praise. It goes straight before the title, with no 是, and belongs to reviews, reports and essays.
The title is a noun phrase (奇迹, 经典, 典范 "model", 大师 "master") or one of a few praising words that work like nouns: 完美, 一流, 经典.
A comparison or a range often comes in front to say among what the subject stands out: 在同类产品中, 在中国历史上.
堪称 is praise. It doesn't introduce a plain name, and it doesn't go with a neutral or negative label.
In speech, 称得上 says the same thing with less ceremony.