不失为, 堪称, 称得上 — worthy of the name

規則 不失为 = may still be counted as — a GUARDED compliment conceding one merit: 这不失为一个好办法。
堪称 = deserves to be called — an EMPHATIC one, at the top of the scale: 这部作品堪称经典。
称得上 = counts as, all things considered — the spoken one: 他称得上是个好老师。
All three must be followed by a NOUN PHRASE, never an adjective:
RIGHT: 不失为一个好办法。 WRONG: 不失为很好。