I say I don't understand why people like it so much because of my personal and extensive history with the product. Also M205 is a far different horse than Speed so it's really not that comparable, although it might seem to be at first glance. M205 was always good and worked as advertised, actually better since day one. I can't say the same about Speed, in all my testing of it, it never performed as advertised at all. I've had these same arguments many times over about 7 or 8 years ago when Speed first came out, it's crazy how the same things pop up again.
Also, isn't it just silly and totally defeats the purpose of an AIO if you need to top it with something? You're far better off using a good polish and a sealant.