I have Thomastik- Infield Jazz Rounds. I don't know anyone else who has them. I guess they are fairly new. Lots of people like the flats, but I have read that they're not particularly popular with single coils pickups. I have had no direct experience with the flats, & comparing my rounds to them might be "apples & oranges". The rounds come in smaller gauges: .118, .089, .068, .051. 043, .029. Using those strings on my Ibanez SR406 (upon which I formerly had Carvin J99 single coils) I noticed that the slinky gauged B E A D strings sound surprisingly round & robust (still relatively light & focused) The G string, with the non slinky 43 gauge string sounds very lean & twangy. So lean that I can't play the G, A-flat, A, B-flat (frets 1, 2 & 3) on the G string at all. I honestly have to play those notes on frets 5, 6, 7 & 8 of the d string to make them sound right. The G string doesn't integrate with, or transition well to the D. The A & B-flat are the absolute worst-like a guitar not a bass. The 29 gauge C string is what one would expect all C strings to sound like: light & high. Played on the 5th fret of the G string the C integrates adequately. When I soon get my DX6 double coil humbucker replacement & solder it in, I suspect that the Godawful twanginess of the G string will seem less problematic--particularly using just the front neck pickup, but that's just a guess. I think a lot of the problem is simply the interface between the string & jazz pup. We'll see. I have read in this forum that some others don't like their TI flats w/jazz pups. I replied by relating my problems with my round G string sounding thin & twangy. Someone pointed out that it may seem counterintuitive that the .43 gauge would sound rounder if it was commensurately smaller in gauge to the other slinky gauges. He based his observation on the notion that a thicker gauged (G) string is stretched tighter, & will produce more twangy overtones. As a rule I have observed the opposite, a .045 G string is going to sound thicker than the same brand & make .040 G string. However, in the case of the TI rounds, I suspect that say, a .037 or .038 G string would have far less tension & sound fuller & rounder with fewer overtones. (That is if a TI .037 actually existed.) I think the guy had a point. TI boasts of having balanced tension in the set, but the .043 has WAY more tension than the other strings--more than 34 .lbs compared to under 27 lbs. of .118 B string. Another observation was made by Jason (who sold me the TIs). G strings tend to be twangy because they have only one outer wrapping. That tends to be true of G strings, but sheesh, again, my A & B-flat sound more like it comes from a guitar than a bass. While the low strings sound focused, the G seems downright beamy! I suspect that once I hear these strings with my humbuckers I will like them more. (Otherwise I will get rid of them AND the Ibanez.) The TIs feel good, & seem to have the potential to be a nice kind of generic light & smooth sounding jazz string. But hopefully not too light.