I'm going to purchase the iMac with 5K display and I dont know which drive to purchase. I'm edging towards the 3tb fusion due to the fact that I'd prefer the extra space. Will there be any noticeable speed difference between that and the 1tb flash? Will either of them give me any noticeable advantages over the other? The price difference isn't an issue for me, I'm just unsure which one to purchase. I read once that the flash drive will give my iMac a longer lifespan & stay at top speed for longer than the fusion, is this true?