Ruby programming language now can be called as mainstream programming language. If you are still not sure, checkout the site according to which Ruby now got the 13th position from top. I liked Ruby always and still prefer Java for enterprise level. Java has continued to maintain the top position and will remain there for years to come. I am sure that Ruby will gain the position in coming months and prove its strength as a mainstream language. I am fan of both these languages. Oreilly Ruby blog has also post written by Curt Hibbs a post titled Ruby declared "mainstream", check that out.