I've heard great things from other people about the JJ KT88's, and use them myself in my Sunns and I like them very much. They sound very nice and are reliable. I haven't heard very much buzz about the EH KT88's, and that probably means that they don't sound particularly spectacular and/or they are reliable, or both. If they were unreliable there would be news about it on the boards, and no one talks about them. No one seems to be using them from what I gather.....everyone seems to be stuck on the JJ's, the SED Winged C's, or the EI KT90's, although the prewar EI's were WAY better than the current stuff, and the EI's are usually liked better for hifi applications than guitar or bass.
Greg