I have narrowed my new delay pedal down to these. Besides the obvious Tap Tempo, what are the differences in these pedals? I know at some point, there were changes in the chips. Which of these came first? Does one sound that much better? Are they that different? I've been doing a lot of research and can't seem to find what I'm looking for. Anyone have experience with both these pedals? Also, it will be replacing my Deluxe Memory Boy...would I notice a big difference? Thanks in advance.