Thomastik Rondo cello strings work on many different instruments but were particularly composed for soloists with modern instruments. These strings offer abundant modulation in all registers and an outstanding balance of warmth and brilliance. Even in the delicate pianissimo they reach and keep their full potential and projection.
My luthier grinned when he saw Rondos on my cello and implied that I had fallen for "expensive new string" hype. I grinned back and said "yes but these are worth it". I think they are very well balanced and save me from messing around with mixing brands.
I have used Versum, Versum Solo, and Rondo on both of my cellos. They are all really excellent, long lasting strings. I settled on Rondos for both cellos, for me, they are extraordinary. Here is a link to a comparison video