Yeah I only buy F mount glass because of the speed booster and because it is so versatile and future proof. I could rent a red epic and I already have a good set of glass to use on it.
How much are you looking to spend and what focal length?
Personally, I don't need a macro lens enough to justify spending $800+ to have one in my bag. I just have a set of extension tubes that I have gotten good results with. A little bit of a pain to work with compared to a real macro lens, but at a tiny fraction of the cost with little compromise on IQ.