These strings are seen on almost every jazz bass in the country, for a reason!
Although i have strayed away a few times, trying the likes of velvet and helicore, I keep coming back to these Spirocores as the sound consistently great.
Growly, with a lot of life, but not overly toppy these strings sound great un-amplified and (importantly) with a pickup. They also are very long lasting and (once you get past the initial 'zing') sound very even throughout their life.
They Can be bowed, but I think its fair to say the are primarily a jazz string with Pizz in mind, as some players (including myself!) find them a little unruly under the bow.
Overall, a great set of stings at a very good price.