So, I am not in touch with my college professors, besides I did not even do well in college (below my potential

And hence landed up in S/W programming - and have worked in great projects, with good companies all these years. After all these years, I felt like going back to higher studies, for various reasons.
So - effectively, I do not have anyone from college to write recommendation. How do universities view recommendations just from professional experience - and none from college? I am not targeting top universities (and I can not afford to, after what happened in subj-gre). I am equally inclined towards courses of the type - financial engineering, some mix of maths and computer science, or just computer science.