I use these on a fender p bass. They are a really good compromise between a flat and a round wound string. If you want a lot of versatility in your sound, these will do it, going from thumpy flat tones to clear ringing round ones (almost!). I'd say they sound more like flats than rounds, so that's why is just doesn't quite make it to covering all angles - think worn in rounds for the 'round wound' tone. Between the tone pot and amp EQ these give a lot of variation - so great for a gigging bass. They last a long time too, I just replaced mine after 2 years, but I'm thinking they could have gone on longer, flat style.
A small warning though, allow time for these to break in on the bass - at least a couple of weeks. Brand new they sound hollow and uneven, but eventually they even out to a mellow even tone.