We have just released Tripal version 3.0 release candidate 1 (7.x-3.0-rc1)!
We have worked to test as much as possible and therefore make this a "release candidate". This is the step just before stable 7.x-3.0 release. There will be no major changes to infrastructure or design in later releases as this release represents a completed design. The only exception is some additional updates to come for web services. We are currently in the process of upgrading several Tripal sites to use Tripal v3 for production so we will have multiple Tv3 sites online soon!
We have improved the User's Guide and you can find it on the Tripal.info site here: http://tripal.info/tutorials/v3.x. We will be adding more content within the next several weeks as well.
Please provide bug reports to our GitHub Issue Queue at https://github.com/tripal/tripal/issues
1) Tripal v3 is backwards compatible with Tripal v2. We have switched content types from Drupal "nodes" to Drupal "entities" but you can continue to use your current Tv2 "nodes" and templates as these are still supported. You can migrate your content to the new entities as time allows and at your own pace.
2) All data is categorized using controlled vocabularies. Once web services are completed this will allow for improved data exchange between Tripal sites and collation of data from different sites.
3) Tripal is no longer dependent on Chado for organization, although Chado is still the primary data storage back-end.
4) Because data are now organized via controlled vocabularies, the organization is more intuitive. For example, you can create a "germplasm" content type rather than a Chado-centric "stock" content type, and data from your site will be shared via Web Services as germplasm data and not "stock" data.
5) Content is uniform: what you see on a gene page (or any other content type) is the same data that appears in web services and is available in Drupal Views. If you hide a field (i.e. piece of data) it is hidden everywhere else.
6) Tripal v3 fully adopts Drupal's Entities and Fields. This means you no longer need to edit PHP template files just to move or hide data on your pages.
7) You can customize your page layouts if you do not like the defaults that Tripal provides without any programming. No more PHP templates. Using Drupal extension modules such as Display Suite or Panels you can lay out your pages how you desire.
8) For developers, Tripal is now more object oriented! If you need custom content we have expanded our API to more easily support integration of new fields. This includes fields to support brand new content, or new "formatters" to change the way a field looks.
9) We have added a middle-layer separating the data storage back-end (e.g. Chado) from the data presentation layer. This means we can more easily support other storage methods such as no-SQL options, direct access to files (e.g. indexed BAM/VCF), etc.