Interbus is not bad, but the support and product spectrum is relatively limited.
Phoenix (and a few others) is making Interbus modules for various PLC brands, but they cannot make modules for all PLCs. Almost all of the PLCs supported are old (or very old !).
Examples:
There are modules for AB PLC5 and SLC500, but not for ControlLogix or CompactLogix.
There are no modules for Omron, Mitsubishi, LG, AD, Telemecanique etc. etc.
If you are looking for a bus standard with wider acceptance, then look into Profibus or DeviceNet.