DT Register offers a great deal of handling for complex event registrations, like ours. Flexible field types/arrangement are critical.
Ease of use
Easy to understand, but there are tons of options, so there is a learning curve to get going.
Developer monitor forums and actually respond! Can get information on backend database to write custom wrappers when necessary.
Documentation is a major version old, but the videos are helpful and mostly still apply.
Value for money
Exception value for us. We run one major event a year and this is year three on this extension.