I guess this is explained by: One is what foreigners would write and one is what Japanese would write. We all write arigato. But all my Japanese friends write arigatou. And the correct way of writing is ありがとう (arigatou)

The reason why isaburo would be more of a hit than isaburou can be explain by... the foreigners would type isaburo, but the Japanese would not type in roman characters (isaburou) but rather いさぶろう。In any case, thanks for the answer. I am going to Kagoshima, Kumamoto and Nagasaki next year, and I want it to be slow and relaxing.. (tho i will be sweating buckets since I will be there in July) I'll work this into my itinerary.