Hi Jeremy: Not exactly sure on your question "any difference for the Allen Bradley side of things?", but think you are asking is there, and what are the primary difference between the LogixPro Simulator (AB) and the Siemens PLC Simulator Bundle, besides just brand specific differences.
The short answer is YES, night and day.
If you have used the Logixpro SLC 500 simulator, then got to bin95.com/siemens-plc-simulator.htm and you will quickly see all the differences. A couple of the primary differences is with Siemens software and therefor the siemens simulator is that the operating environment and user interface is laid out like a PAC (like RSLogix 5000), not a PLC. But both use ladder logic as the programming language. The Logixpro has 9 pre-designed simulations, up to 32 discrete i/O. The Siemens PLC simulator bundle have 20 (more realistic) pre-designed simulations, plus the ability to easily create an infinite number of your own custom simulations. Plus unlimited I/O, not only discrete, but analog I/O too! Plus the siemens plc part of the bundle, has most PLC instruction set at your disposal, not just contacts, timers and counters like the LogixPro is limited to. There are many more advantages, but those are some of the primary ones.