Thanks for the review.....
....... I will have myself a drab finish one day.
........ there is another argument to the whole paid/given for review debate.
If someone has paid for something with their own hard earned cash then, they often 'want' to like it more, sometimes people don't want to admit they've wasted their money and other times it's just something they really liked and wanted to buy it in the first place which obviously means they have a positive bias towards it, not many people buy stuff they don't think they'll like ..... and if it has obvious flaws maybe they won't point them out because they might be selling it in the classies in a couple of weeks. .... how many times have we read "it's an amazing tank/mod ... but just not my thing" ie, it's junk.
If you get something for free it can be easier to be honest, you have no money tied up in it, you have no expectations, you have none of the 'Oh I really like that, I'm going to buy it" bias. The fact it wasn't paid for just enables the review to happen when it's something you wouldn't have spent your money on.
My VIM (not sent for review but sent for testing) is in bits in the bin because I wanted to really have a look at what's going on inside, and if anyone asks me I can tell them... I know what battery it uses and that it is possible to replace if you know what you are doing and can solder, I know the quality of the internals and things that could be problematic in the long term. .... if i'd paid for it there's no way I would have ripped it apart and taken gouges out of the side to test the finish and durability of the plastic.
I don't think it's as black and white as you think, there can be honesty and dishonesty in both cases I feel.