24x7 3.4 or 4.0 java version...which is the better choice

Is there a preferred scheduler (24x7 or 24x7 java version) to select and implement?

Are the long range development plans to continue development of both versions?

Both versions are going to be merged into a single product. It is not going to happen tomorrow, but it may happen in a foreseeable future. We are actively working in that direction.

If you are just starting a new implementation, it is recommended that you use the Multi-platform versions. If you start with the Windows-only version, chances are that you may need to spend some time during next major upgrade to verify how job definitions get converted to the new format compatible with the Multi-platform version and make some adjustments if required. Also the Multi-platform version has much better scalability and is recommended for large projects, especially for multiple-platform projects.