Alright, there are several things wrong with your post. First, why do you call yourself out as being biased? That's rather stupid, and I don't see the point in it. Second, you fail to understand what the word impartial means. Impartial means you don't favor one over the other when making judgements, and will highlight merits and faults regardless, not that you love them all.
And yes, it's true that about 99.8% of DS games don't work on the R4, therefore rendering it completely useless. I guess you're right, burn all the R4s because Worms and Deltora Quest don't work. And when you say "100% compatibility is pretty much available on all carts except the R4 and older carts", what older carts? Everything, right? There aren't THAT many flashcarts out there, so among them R4 still stands as one of the best. Name 5 other DS carts with absolute 100% compatibility, and I will stand proven wrong.
And you say you "eventually" expect it to get more popular, yet is it there now? We live in the present, and speculating about the future does nothing to change the here and now. Even though incompatibility is a big issue, it's *easily* fixed in comparison to something like say, soft reset or the Acekard's lacking download play.
How exactly do you know that I made the judgement favoring a single cart over another? I got all of them under the same circumstances, I tested all of them using the same tests, and my judgement is based on the cart's same tests. I used the same files to test them, I used the same games to test them, I don't see how you can call me bias. Just because I don't like a cart that you have, and I like a cart that you don't have? If anything, you are bias as you only have the R4.