The Labella's LTF have a very warm/dark smooth sound (The Labella tone) and are really smooth to the touch.They are lovely to play, I found the tension on par if not a little less than Tomastiks, I recall not liking the feel at the time.
The Tomastiks have a more pronounced mid range tone and a sweet treble when new, which later dies off leaving a warmer thump. I've had these on a few of my basses, before I realised the feel wasn't right for me. You can feel the wraps on these strings, but not a harsh feel at all, and for want of a better description, they felt "plasticky"
Both great sounding strings, very easy to get about on, but I think next tine I get flats, it'll be light standard Labellas, they seem to have the classic tone.