The hashrate of each miner is subjective, it has everything to do with the algorithm it works on, in other words, a car that does 50km/h competing against 20 old men on wheelchairs is certainly a lot slower than a car that does 300km/h, but when latter is competing against a dozen ballistic missiles, the slow car is "better".

So ya, don't compare different miners from different algorithms, there could exist a miner with the speed of a few mega hashes that makes more "money" than a truckload of the fastest Sha256 miners, but you need to keep in mind the future competition, SHA256 difficulty is hard to move, 5% is considered a lot, whereby the overall difficulty of other smaller algorithms could easily double in a few days, so ya, there is more to it than meets the eye.