You will find that the longer the song the more frequent issues appear. I don't have any problem running sequences back to back with no break between if that is what you want to see. Just make sure your music and sequence end and start at exactly the same times. I get breaks between sequences when I do not pay attention to the music fade out times or I don't make sure effects run right to the end.
The longer the sequence the longer the load time, the longer the copy time, the longer the save time, harder to edit, and on and on. In my experience most folks only watch a show for 10 min or less, so having something really long means nothing to the majority of viewers. Folks who draw a lot of traffic usually end up making the show shorter in order to get people to move on. I've seen references to folks cutting their show to just one song in order to keep the viewers moving. I know of 3 shows in my area who have had so much publicity that they draw tons of viewers and end up spending their evening outside directing traffic. Not something I would look forward to. On the other hand do the show for your self and enjoy it, your choice.
