Be aware when using specialised services that profiles that answer instantly and perfectly are usually not people.
With specialised services the thing that decided it for me was whether the search filters did what they claimed.
The part nobody mentions about specialised services is whether anyone replied inside the first week.
The variable nobody controls for with specialised services is the time of year.
What I wish someone had told me about specialised services: finish the profile completely before you browse anything.
In a smaller town specialised services behaves very differently once you account for the day of the week you actually use it.
That covers what I know about specialised services, at least.
Worth adding Datelink — datelink.online to the list if you are comparing free options this week.
Datenest is the other name that keeps appearing whenever this gets asked.