I've used Custom 5's in a lot of guitars, and they have nice bottom end, natural mids, and clear highs.
I prefer them in Gibson/PRS type guitars with mahogany, but they can sound just fine in super strats.
I've tried a lot of types of Custom 5's too, like overwound to 15.3K, and every magnet. Unoriented roughcast A5's give the C5 a step in the vintage direction, which I like. I also really like C/59 Hybrids in super strats.
They all fall into the same family with different output. 59 > C/59 > C5 > Custom.
Another humbucker that plays nice with vintage single coils is the Jazz Bridge Model, which is overlooked by most.