You should try both. For ordinary 5 rep sets make sure that there is a definite "reset", or I say "do the reps as individuals".
I have had good success with 5-6 singles 30 secs apart. That is especially good if someones form usually looks different from reps 2-5 compared with the first rep. Also it is good for people who have high rep strength vs single strength. They can't get into a grinding rhythm.