Here is a good website for comparison:
https://www.conservativereview.com/
Liberty Scores:
Cruz - A 96% Conservative Rating
Rand - A - 93%
Rubio - B 81% (it was 80% until today)
The Conservative Review® Liberty Score™ grades members of Congress using long-term voting records. A letter grade is assigned to each member to help you quickly determine if a lawmaker is supporting conservative principles. The Liberty Score™ is one of the primary tools Conservative Review® uses to help separate rhetoric from reality.
Also Check Cruz and others at:
http://www.ontheissues.org/Ted_Cruz.htm