That's one of the main question to ask before making the final choice:
The long term solidity of such product.
Once it is set up, the system in place MUST keep on working for years! Basically there must be no time limitation.
+ It needs to be solid and stable.
With what i say with PHPBB my guess is that a coder can easily transfer the database o a new system if needed.
If a new better tool appears in the future or somehow that system becomes unstable, then it is always possible to shift to a new tool.
I have no doubt that this can be done without data being lost in the process.
Everything is on database and databases can be reformated any time.
Yes! I know it is possible and therefore the risk of data loss or system collapse is close to non existent
What about the long term stability of the product?
Well... That product has been on the market since I started online 6 years ago, so it one of the top solid products on the market.
What about updates?
At this stage, only 6 months are provided - That's a pity but imagine that 5 years from now many new upgrades have been added and the product has been deeply refreshed, than buying a new version is an option.
If you compare this one time payment with ongoing membership options, the price for that one is still ok, even if you need to buy it again 5 years from now.
The reason why this decision to go for it or not is not taken lightly is because a system like this one will ad an essential set of new features to the site and could be there really long term.
Yes, once it is on, it will be tested and things can easily be reversed if needed