Adjective + は + Adjective

Question

I think I have heard this kind of sentence before, and searching on google I found a couple instances. When you repeat an adjective (and perhaps verbs as well) to show that you've done / feel a certain way but not to the point that the listener might expecting. Or maybe to soften your negative opinion.

美味しいは美味しいけど。。。 It is good but... / it is not that it isn't good but...(reminds me of 美味しくなくはないけど)

好きは好きだけど。。。I do like it but... / it is not that I don't like it but...

couple instances I found online:

おいしいはおいしいけどね

好きは好きだけど、どの好きかわからない

So my questions are:

1 - How grammatical is this? Is it more like something you'd only use conversationally?

2 - Can it only be used with adjectives, or maybe with verbs as well? (eg. 観るは観るけど、興味があんまりない。)

Answer 1

1. It's perfectly grammatical. In my opinion, it's an ordinary grammar pattern that can be used anywhere. It's not particularly formal, nor casual, nor literary, nor slangy.

2. It can be used with any type of predicate (noun, na-adjective, verb and i-adjective), but people often use に as well when the repeated word is a verb. See my previous answer for examples.

Answer 2

1. Your assertion is correct. This is mainly a conversational phrase. Not a formal one. For example おいしいはおいしいけど、あまり私の好みではない。 It's good, but it's not really the kind I prefer.

2. In the case of verbs, people usually use 見ることもあるけど in the way you used it or maybe たまには見るけど. Another somewhat related phrase would be 見なくはないけど. This is used to say that the amount you do something is not zero.