Bought a Sigma OM some weeks ago. Changed the strings to a set of Labella 010 on the guitar upon arrival. Great strings. I play fingerstyle and chords in open E tuning with my thumb, mostly. As the Labella's are great strings, the guitar still got a mid hump sound that is warm (and gentle) - but for my style, the guitar missed something in the treble register.
As I need more attack in the sound as I play with my thumb, I gave the Savarez Argentine a try. What a relief it was!
The guitar sounds way better, as the mid hump was replaced with less warmth and the treble register is much more noticeble without sounding harsh. This is using my thumb when playing. Do not play with a pick, so this has not been tried. But without a pick - these strings are gold! Even fingerstyle. The guitar sounds more "dry" with a little less bass, but the bass is clear as spring water and the treble range is much more complex and airy. I have tried so many strings and brands before, but my gamble on these strings was pure bliss!
One other thing: the feel and "touch" are great on these strings. Always rub new strings with GHS Fast Fret before use. But these strings did not need Fast Fret to feel good. No machine oil on these strings when new.
If you play with your thumb or don't use a pick - and feel your guitar sounds a little dull or lack something, these strings are definitely worth a try. Not only for Django-jazz style, these strings.
The only bad thing (for me): I would like a thicker low E string (050).
