A bit different understaning. Seems that GridGain support JMS for its Discovery and Communication SPIs:I actually prefer GigaSpaces as a grid provider because they provide JMS out of the box.
GridGain and Gigaspaces are of different positioning. GridGain focus on Compute Grid and Gigaspaces focus on Data Grid. In fact, they are not multually exclusive. GridGain is actually providing Gigaspaces checkpoint SPI implmentation out-of-the-box.It's a different model than GridGain, and more closely aligned with the data than the processing., hence it is easier to imagine transactional concerns being adequately covered.