Yes, I think I prefer to know. Some youtubers are very clear about that but that doesn't persuade me to trust their reviews . I don't watch any of them now cause all the ones I used to watch were really promoting gifts, some are worse than others but it gererally felt like sitting in front of the laptop to watch a 20 minutes ad.
My daughter works for a PR agency and she recruits youtubers to review products and they do get paid, I don't think the youtubers reviewing shaving stuff do it for money but certainly do it for the freebies which saves them money anyway.