I've given up putting too much weight into the numbering on Tripadvisor. Especially in Dubai, the difference between positions is extremely small. It's also clear that many people on Tripadvisor rate the hotel based on their expectations/price, which can absolutely skew results, as you're generally going in expecting more from a Conrad than say a Hampton Inn.

eg, The DoubleTree Business Bay is currently #30 on the list, with a score of 4.5. The Conrad is, as you say, #118 with a score of 4.5. (The scores are no doubt different, but it's hard to know how much given the rounding)

I've stayed at both of those hotels, and whilst the DT is great, there's no way I'd consider it the equal of the Conrad. However as DT's go it's certainly well above average, whilst the Conrad is similar to other Conrad's I've stated at - which says as much about the brands themselves than those specific hotels, and I could easily see people giving the DT (which they paid $100/night for) a higher score than the Conrad (which they paid $300/night for) - not because it's "better", but because it's better compared to your expectations going in.