It really depends what you're planning to do. And without knowing what you're after, our suggestions will be based on what we don't know.
Invision Community (v5): Invision Community has a dedicated user base and is recognized for its feature-rich and aesthetically pleasing design. The upcoming v5 software is expected to bring even more enhancements. It may be a strong choice if you appreciate its current features and anticipate the improvements in v5. The customization is only a tip of the iceberg so far.
Xenforo: Xenforo is known for its user-friendly interface and a variety of add-ons. It's generally more affordable compared to some other options. Many hobbyists find it efficient and suitable for their communities. Development on XenForo is however a bit stalled.
WoltLab Suite: WoltLab Suite is a comprehensive community software suite known for its flexibility and feature set. It includes a forum, CMS, and other community-building tools. It's highly customizable, making it suitable for a wide range of community types. Users often appreciate its performance and responsive design. And they have some great 3rd party development too, which are all reasonably priced!
vBulletin: Upgrading your existing vBulletin license to version 6 might be a solid choice if you're already familiar with the platform. Version 6 includes improvements and new features, so it could enhance the user experience. However, I find vBulletin a bit outdated and less packed with features.
Other Options: phpBB, MyBB, and Discourse are some alternatives. They might require less upfront cost, but the features and user experience are less good than paid software of course.
a few questions to consider:
- How important is cost-efficiency for this project?
- Which software are you most comfortable with?
- Do you have any specific needs or preferences that these platforms must fulfill?
- Would you be open to exploring less costly or even free forum software alternatives?
- What's your goal of the forum ?