I recently gave a set of 9050ml's to a buddy. He put them on his bass, and he absolutely loves them! I heard him play his newly flat strung bass at a local jam night here recently. The tone, well, it sounded punch-you-in-the-chest punchy, something that has been sorely missing from most concerts and club gigs I've witnessed for many years. It convinced me, that round wounds, which are on my 5 string performing basses, are not necessarily the be-all end-all answer to bass tone.
Old school gut strings for uprights made somewhat of a comeback recently, but the upkeep hassles will prevent them from ever overtaking steel strings again.
Flatwounds are great sounding strings for electric bass, the solo voice on my Fender P-bass in the upper positions is much more pleasing, and punchier than with the rounds. Try a set, 9050 ML Fenders. or LaBella Deep Talkin' bass, or the brand of your choice... you may be surprised how much you like them!