While I have never used affiliate links, I have received free gear, regularly, and I maintain that I have not been influenced by any company. Consciously at least.
I say consciously because no matter how unbiased we try to be, there are always biases that we may not even be aware of. Something as simple as having a good relation with a company can mean that we will want to like something and automatically search for the good points where possible. This can even be the case with something as trivial as a colour. If we are huge fans of pink but hate blue, then something that is pink is going to automatically start off on a better foot than something that is blue.
What I do try to make clear is that anything I say or write in my reviews is just a personal opinion. No one should be basing any purchases (or avoiding purchases) based on what I say in a review. When it is not possible to try something out (which is the case for many many people, especially in the lower budgets), then all that is left is to gather as much information from as many people as possible and make your own guess. Because that is all it is, a guess.
I review for fun and, to be totally honest, most of the time it costs me money to do so. When I receive stuff, even if it has been sent free, I end up paying for import a lot of the time. I also pay for a website, for shipping in many cases and other things along the way.
Yes, I get free gear. Most of which gets used for a week and then gets stored along with other gear that only ever comes out again if it is to be compared to something else. Even the items that I do like and enjoy, I don’t get to use them that much because I am usually trying out whatever is sitting on my desk.
This is by no means a complaint, I do it because I enjoy trying out new gear, I am not obliged to do it and I am lucky (most of the time ) to get my ears on a lot of stuff that I would never end up hearing otherwise. However, I certainly do not do this for profit and I sure do not want to influence anyone into using their hard earned money to buy something that I am not being 100% honest about.
I have a terms and conditions document that I send to any brand or store that contacts me and I ask them to read it and agree to it before sending me anything. It basically says I will give my own honest opinion and disclose the origin and any requests. I make it clear that if they don’t want that, don’t send me anything. I like to be clear with those who send me stuff, be clear with those who read/watch my stuff and, above all, clear with myself.
Basically this overly long post is to say that there are all kinds of reviewers out there and it is impossible to know which is which. Yes, you can get an idea but you will never know for certain.
I would never recommend anyone to put their trust blindly in a reviewer and I include myself as you don’t know me and those who do, don’t need to watch my reviews.