I don't think arguing over which parade has better floats or better music is going to do any good. There will never be a definitive answer to which is best because people have different tastes. Someone who loves MSEP and saw it in its prime is always going to enjoy it more than spectro, just as anyone who saw Spectro as their first night parade will defend it from any criticism.
What surprises me is how the popularity of these parades seems to have eclipsed any concerns management must surely have of how outdated both parades are quickly becoming, especially MSEP. I mean surely when people see MSEP, a large enough portion of them must think it looks terribly behind the times in the middle of a theme park which with locations such as Tomorrowland and a nearby Park Epcot, has always been at the forefront of new technology.
I know the reason is undoubtedly partly due to budget, but surely at some point management has considered scrapping MSEP and replacing it with something more modern, yet its overwhelming popularity seems to ensure that it continues to run year adter year, decade after decade.
Dreamlights in Tokyo is a fantastic parade, and I'm sure it would do great if it was replicated or if a similar parade produced in the US, but if the people who flock to the parks are so apparently in love with the current offerings, why would management spend a load of money on a parade that people may not like when the one they have shows no signs of needing replacement? We all remember what happened to Light Magic.
I guess what I'm saying is, MSEP and Spectro are probably not going anywhere anytime soon. At least not in the current economic climate. They both have such devoted fans, I just personally find it surprising that a parade as old as MSEP is still running, when in my opinion it SHOULD have been replaced by something more modern by now.
Think about it, with the technology we have today, the possibilities for a new night time parade are almost endless!