These are all anecdotal information from experience and hearing founder friends. A US LLC is a good choice if your primary/majority of paying customers will be from the USA. An LLC has a lot less compliance and taxation headaches, but it is not well separated from an Individual taxpayer -- it is akin to an extension of you (of sort). This makes perfect sense for a US tax-paying individual (resident with an SSN). However, it comes with its own taxation headaches once you grow bigger as you are not paying individual taxes in the USA. At this stage, you are likely to get an ITIN.
If you have decided that a corporation in US makes sense, then it might also makes sense to stick to the C-Corp.
So, my point is -- talk to a lawyer. You are already succeeding, and you can afford a good one. Plan for the future, and if you have to pay a tad more now for that ease in the future, I suggest you do that option.