Cinematic Strings 2 (CS2) is a much-loved library that has been out for several years and is still very popular with students and professional composers alike. Recorded in a large concert hall, CS2 has a very big lush sound and is one of the easiest-to-use professional-level string libraries on the market. CS2 is 22.5GB installed and priced at US$299 (excl. tax) - the price was reduced from $399 when CSS was released.
So CS2 has a concert hall sound, and is easy to use straight out of the box; CSS has a scoring-stage sound, has more articulations and more realistic legato. To help you choose please listen carefully to the demos on the websites as they are true to the sound (very little EQ or reverb in the CS2 demos and none in the CSS demos). I'd also recommend watching the videos to get a feel for how the libraries work, read reviews etc. And please check the minimum requirements for each library. If you would like further information please don't hesitate to contact us at firstname.lastname@example.org.