Salou or Benidorm.
Easy answer for me: Salou!!!!!
I didn't think Benidorm was cleaner than Salou, neither are perfect on that score.
Salou is less high rise, the beaches in both resorts are very good, both have the EC blue flag.
Theme Park in Salou is better than Terra Mitica (only my personal opinion)
Salou felt safer.
The seafront in Salou is lovely - you can walk around the rocks where there are loads of cafes - very nice atmosphere or walk along the wide palm lined prom.
Benidorm has a better old town than Salou it has to be said but other than that I would rather go to Salou anyday.
I'm the first person to stand up for Salou, anyone else out there?????????
Have a good holiday wherever you go. Both destinations have the ingredients required for a good holiday.