The TI PowerBass are very flexible, perhaps not as much as TI Flats, but still very flexible. They have a fairly bright, edgy sound initially, then after not long at all become very deep and warm.
I think they are great quality strings, although not my personal favorite.
Here's a sound clip with them brand new:
and about six weeks old:
I hadn't played them very much over those six weeks; it seems that most of the tonality change occurred with them just stretched out on the bass, just sitting there.
I did try the TI Jazz Rounds once, but I don't remember a great deal about them. I found the tiny gauges off-putting, though I've read others be quite found of them.