Rubbing up against other parts or even against your skin at times. For such an expensive toy I would absolutely expect better quality paint. MP5's paint has no such problem, and that toy is 10 years older. Although admittedly MP5 does suffer from rust on its die-cast metal parts. MP36 has some die-cast metal parts too, but they're painted over (e.g. feet, base of stock-stand etc.), so hopefully the paint will help protect those metal parts from rust.

I haven't put batteries into mine, but it sounds like the same voice chip that they used for reissue Galvatron.
MP36 & reissue Galvatron sound chip comparison video
As you can see (hear) the voices are exactly the same. :/ Although Katō Seizō (the Japanese voice actor for G1 Megatron/Galvatron) passed away 3 years ago so while he was able to record voices for Galvatron he was unable to do so for MP36. Perhaps they reused the same voice chip as a tribute to Katō. They could use a sound-alike but I'm sure that Japanese G1 cartoon fans would appreciate them using Katō's original voice.

For such an expensive toy I would expect them to at least use decent quality paint that didn't rub off so easily. It reminds me of the crappy paint that they used on MP9's spoiler (yet Hasbro's version has much better paint quality on its spoiler). For this reason I voted, "Only if cheap." At least MP9's spoiler only covers one small part of the toy and only scratches when you slide it in and out of his trailer -- Megatron's main body paint which covers the majority of the toy is prone to rubbing off. And being metallic, there have been a few times where after handling this toy my finger tips have been sparkly.