I find the rental market tough enough to navigate myself which is a pity as i would have plenty extra cards as well. Not only that but I would probably rent some of the rarer ones too for my collection to compete higher. I think it could do with a few tweaks to make everything clearer for users which would increase it's use. For now I'm clearing out a lot of my extras to try and build a more powerful main deck.
Have fun with whatever way you go from here.