These are two different parks. I love Platty becuase it is the best pure DH on the east coast. It really is the Beast of the East
Mountian Creek is a resort which has DH as one of their many amusements. Platty is open only on the weekend, while Mountian Creek is open every day from the 4th of July to Memorial Day. Both are great in their own way.
It is mandatory to bring a folding camp chair to Platty or they will not let you ride
Creek is very rough and not very steep; super tech rough style gnar, but no clench-your-bum stuff. It also has very active trail maintenance and much of it would be considered 'groomed' - very fast lift and decent variety.
Plattekill is much more than Gnar, but its not the groomed 'bike park' that highland, Creek or much of whistler is. Its rough, loose, lots of steep - and plenty of OH SH*T opportunities.
Both are great spots, def very different - I am the full on Plattekill fan for 'pure' or 'natural' DH - and both trails and comradery.
Almost everywhere in the NE (I cant speak to anywhere else but Whistler and SnowShoe) is a pretty dope place to ride!
Both are a lot of fun. It depends on what you are looking for and your skill level. By the sounds of it and what it sounds like you are looking for, I would go for Mountain Creek. They have a great variety of trails and it is very fun. I have made the 12hour roadtrip 4 times in the past 2 years.
pff you can't have a better decision to make. mcreek is much more urban and plattekill is much more rural. beers in the parking lot at platty is no problem, actual selection of food at mcreek is nice. Great riding at both venues. Fast lift at mcreek, two lifts on race weekends at platty. You can have a whole mountain to yourself. More buff stuff at mcreek, zero at platty but enough trails to keep you interested.
I'm partial to platty but that's where I started riding.
toss up really, i think that the GES "events"are run better, but the esc always tries to go with the more "hardcore" tracks. Its a toss up really. I wouldnt really consider it much of a difference-ill be racing both.