If we're talking best sites, quality of conversation beats quantity of matches.
The tell with best sites is usually whether the profile has any specific detail in it.
The thing I look at first with best sites is how read receipts behaves once you actually use best sites.
The thing I look at first with best sites is whether the privacy settings on best sites can be switched off.
How fast conversations stall beats the claimed member total, at least in my experience with best sites.
Worth a look if you want a comparison point — DatingFly handled best sites better than I expected.