I've been waiting for a HT Grieveous as well. My only fear is the price. And that may be my deterrent.
I have the 1st SS release. And yes its flawed, but I've never touched him really after putting him on display. He looks good enough on the shelf from a distance with 2 SS Battle Droids flanking him.
I also have the 1st SS Ex Premuim Format statue of Grievous. But its been boxed up for quite some time. For me thats still the ultimate Grievous collectible.
SS Grievous won't even compare, will look like a Hasbro toy... with its saggy arms.
HT Grievous will be huge and excellent. Moving eyes. Light up sabers. Yes, it will be $500+ but it will be glorious.