Since almost a year now I have been using Presto Balance Hybrid strings on my double bass that I use for jazz and orchestra work (a 3/4 carved, roundback, possibly Romanian, mid-range bass). Presto is the German company that is maybe most famous for their Presto Nylonwound pizz/slap strings that are sold in the USA under the name of Eurosonic. Lately Presto has enlarged its scope, including orchestra, hybrid and jazz strings, and even cello strings.
I tried their Balance Hybrid string, in the Light version (they also come in Medium). These are all-metal strings with a steel rope core. The sound and feeling remind me of the Thomastik Spirocore Weich (Soft), but the Balance strings are much easier to play with the bow. The sound is punchy warm, slightly dark, though not as dark as the Evah Pirazzi's I had on my bass before. The volume is great, they speak easy. The feeling is like the Spiricore Weich or the Obligato feeling: elastic, with a good grip and without the sideward-rolling effect that Obligatos can have. The strings are neither thin nor thick, again a bit like Spirocores.
In the past twelve years I have tried many hybrid strings: D'Addario Helicore Hybrid, Corelli tungsten, Pirastro Obligato, Pirastro Evah Pirazzi, even Pirastro Olive. All things considered, of non-gut strings the Presto Balance Hybrid strings gave me most of what I have always liked in gut strings, without their negative sides. Of course they are not gut strings, but if you know how to do it (experiment how and where to put your energy into the string), you can obtain a sound that's close to the gut string sound. Also for 'modern' players they might be a good choice, since it's easy to obtain a long pizz sustain, to play in thumb position and use the bow.
If I should give one criticism it is that I found the strings' pizz performance slightly better than their arco performance.
I first found out about these strings in Hervé Jeanne's string matrix, this project that cannot be over-praised. Listen to several strings, recorded on the same bass, under similar, controlled circumstances:
http://www.hervejeanne.de/saitenmatrix.php
Info on the strings:
http://www.presto-strings.com/balance.html
Has anybody else tried them?
Gregor Schaefer
double bass player
Amsterdam
Presto Balance Hybrid strings review 
I also need to have the opportunity to bow when needed. I think maybe the Presto Balance Hybrid could be the string, but I'm wondering whether to try the light or medium strings? Could you offer some advice? I have used and liked Obligatos and Helicore Orchestra medium if that helps giving advice on light or medium.
