Services that are not employer-paid are always less ethically sound.
Why? Is it that individuals have fewer companies to choose from, and are more likely to check the entire list regardless of ordering? Is it that employers are the active participants (searching for potential employees vs individuals who just show up in searches instead of searching and applying to specific jobs)? Is it just that employers have more spare cash, so charging them doesn't annoy them as much?
It's that ultimately, the hiring decision is in the employer's hands. Candidates may end up paying even when there are no legitimate transactions to be had (employers are only speculatively browsing talent markets), but employers will pay because there is a burning need to fill their open position. Even if there is no talent immediately available, they can raise offered compensation until they create market demand for their open position.
There are several "personal marketing" or applicant-paid "career transition" services that are outright frauds, and Internet consumer complaint sites are full of stories of such rip-offs. Generally, if anyone asks for an up-front payment to find "unadvertized" jobs, run.
Why? Is it that individuals have fewer companies to choose from, and are more likely to check the entire list regardless of ordering? Is it that employers are the active participants (searching for potential employees vs individuals who just show up in searches instead of searching and applying to specific jobs)? Is it just that employers have more spare cash, so charging them doesn't annoy them as much?