271101 Select existing Survey Script

I need a recommendation for the best off-the-shelf web based survey script to use for modification and customization and my needs listed below. Note, you probably will not be selected to do actual customization modification work. The focus here is merely on selecting the script without any bias, that will be best foundation for building upon. Source: There are scripts available online for open source and licensable, e.g. sourceforge, hotscripts, google, etc. Looking for someone familiar with all the sources and with survey scripts. Would prefer a scan of dozens of options, unless you're already aware and can provide a few solutions that have all of the features required. Bidding: Please include in your bid which of the below deliverables you can or cannot provide. Deliverables: 1) You will need to list the surveys scripts you evaluated, (I've already looked at about 10) or how many you are familiar with, your experience with them, and where you looked. 2) Based on survey requirements, please advise what programming languages, platform are ideal and weight that factor into the survey recommendation. 3) Recommend the Best Survey Script, state which of the below features they possess and preferably ranking in order. Criteria: Scripts should be evaluated on the following basis and priority order, unless any of these features are trivial to modify or add. The surveys need not have ALL, but most. Surveys scripts with most features should be the #1 recommendation : * Customizeable source code ; whether open souce or licensable * Surveys (not "polls" can consist dozens of questions, multiple choice answers, can be setup to be one page, or one by one * Multiple administrators/survey author login accounts * Unlimited Users tied to admin account * Stable, no or few bugs * Can create unique surveys for each user by email/login and report results of each user * built-in ability to email to users * Advanced reporting capabilities... advanced graphics, cross tabulation of responses * Easy, intuitive to add/edit questions (a subjective criteria, but important nevertheless) * Simple and clean adminstrative/ authoring screens with an "Enterprise" / professional look and feel * Advanced question types, e.g. graphical ranking, matrix * Questions can be one by one, or page by page, by a universal setting * Branching logic * Modern technology/language, e.g. Ajax, Flex, etc. , if necessary to ease in authoring and deployment ; however prefer languages that are less expensive to modify, maintain, scale. * Survey to deploy with negligble server latency between questions, if rendered one-by-one * Low Price, should be under $1000-2000, to license (may consider somewhat higher), if not open source. Some examples of previously evaluated surveys: * [login to view URL] (strong contender, but source code not completely available) * [login to view URL] (moderate contender, lacks some features) * [login to view URL] (weak contender, ugly unprofessional gui, lacks features). The below languages are suggestive and not necessarily required.