Resale is both more risky and less risky.
It's less risky in the short term -- You could likely recoup most of what you spent quickly, if you change your mind in the first few years. You likely won't get it all back -- Closing costs, sales commissions.
In the longer term -- re-sale can be riskier in the sense that you don't know what type of further restrictions may come. You don't know what benefits will be reserved for direct owners only. Buying re-sale likely cuts you off from future resorts, but it's impossible to know what that means long term. (In 20 years, will you still be able to stay at any resort except Riviera.. or in 20 years will there be 15 fantastic resorts that are off limits to you as a re-sale buyer).
As to Riviera's resale restrictions -- If you are buying direct and Riviera is your favorite resort (and it's cheaper than GFV!), then I wouldn't let fear of resale restrictions be a reason not to buy.
On the other hand, if GFV is your favorite resort, I don't think the price difference is big enough to warrant dropping down to your second choice.