My understanding is that both will provide asset protection but you have more flexibility with an LLC than you do with an S-Corp at tax time--an LLC can be taxed as an S-Corp if you like but can also be taxed as other entities (or as personal income) if that's more advantageous to you.
It seems like a significant majority of real estate investors opt for the LLC, probably for the above reasons. I did.
I'm neither an attorney or a CPA so the above is nothing more than my personal opinion. In this industry, both attorneys and CPA's tend to give free advice during initial consultation so your best bet might be to find an attorney and CPA that specialize in real estate and ask them.
