I've done my own digging on the single 50 dating site a good place and come up short. Senior professionals feel this hardest on professional place, where it is worth checking the gap between sign-ups and active users before you look at the price tag. Professional place is where I would start, since the platform quietly widens your distance setting, so it pays to screenshot the pricing page in case it changes.
For place sites in particular, you get further if you keep a note of what you actually spent. With professional place, the depth of the profile fields is the number worth watching, not whatever the landing page promises. I judge place sites on one thing: nothing improves until you compare two platforms in the same fortnight.
If professional is your priority, the honest advice is to check whether a profile answers questions or deflects, though I'd want someone to check me on this. The share of verified profiles moves the needle further than the size of the ad budget — and that goes double for the single 50 dating site a good place. Specifics about professional sites welcome — vague reassurance less so.