/e, ʌ, o/ are phonetically true-mid; /ʌ/ is also strongly centralized: [e̞, ʌ̝̈, o̞].
/a, ɔ/ are phonetically near-open; /a/ is central rather than front: [ɐ, ɔ̞].
Between consonants, /i, u, o/ have allophones that are transcribed [ɪ, ʉ, ə], respectively. At least in case of [ɪ, ə], the realization is probably somewhat different (e.g. close-mid [e, ɘ]), because the default IPA values of the symbols [ɪ, ə] are very similar to the normal realizations of the Ibibio vowels /i, ʌ/. Similarly, [ʉ] may actually be near-close [ʉ̞], rather than close [ʉ].
In some dialects (e.g. Ibiono), /ɪ, ʉ, ə/ occur as phonemes distinct from /i, u, o/.