I bought:
27 in 3.7 GHz 6-Core
16 GB memory
512 SSD
Radeon Pro 580X with 8GB of GDDR5 memory
I had a hard time deciding between SSD and fusion and decided to go with 512 SSD for $90 more.
Shipping Date: Expected by Sept 22
Good spec, I'm certain you'll be pleased with it. Sickening delivery delay, just hope you get a pleasant surprise. I wouldn't cancel because you can't assume any new model iMac will be an improvement for you - a bumped up CPU doesn't mean a lot to most of us - and the price and delivery times could be hurtful.