Was your project able to generate user sign-ups or downloads as a result of the Product Hunt launch?

Currently launching today, so we'll find out soon :D. My initial impression is that conversions for iOS apps aren't great.

I didn't launch yet, but I'm 100% sure that the answer is yes. I talked with people who has big number of launches and they told, that if you have a product but can't accept payments better to postpone launch and integrate payments.