I dive with Amigo's, have for years and think they are fantastic. That said, I have been diving with Robbie a number of times, both when he was at Amigos, elsewhere and "Chuck and Robbie's". I have absolutely no hesitation in recommending their operation.
My position on a dive to the Blue Hole is different than that expressed by others here. You say you only have 8 dives. That said, if you were going to be going exclusively on a dive vacation, I would recommend that you get in as many close-in dives as possible and take opportunities to become comfortable at deeper depths before booking a trip out to the Blue Hole.
It is a remarkable dive, a great way to spend a day and the two followup dives are fantastic. Why not wait until you are prepared to enjoy it fully, as more experienced divers?
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A fish and a bird can fall in love, but where will they build their nest?