I often get asked about which type of string is best and which strings I prefer. One of the problems with steel core strings is that they are not as flexible as synthetic or gut core strings and because of this they are sensitive to hard and strong playing. When you draw the bow over strings you are pulling the string thus adding tension to the string resulting with the pitch rising which makes it much more difficult to play in tune.
Another characteristic of the common steel core strings is that the sound is not warm and with some instruments can sound metallic.
I recommend choosing perlon or high quality gut core strings over steel core. The lower the string the more it is affected by bow pressure pitch changes. E strings are too thin to be made of anything else and not much affected by bow pressure since the pressure on those strings is high to begin with. Steel “A” strings also work well for the same reason. D, G and C strings need to be more flexible. Great gut core strings are very expensive and not necessarily good for your instrument. Many instruments crave the added tension from certain perlon strings for producing a strong sound.