@Carlos C. - not a lawyer, so none of this should be construed as legal advice, just ramblings to be taken with a big grain of salt:
1. There is no absolute answer and unique tool/strategy in anything real estate. You need to learn how and when to use all the tools available to you (financing, insurance, management, etc.) and to understand how they fit together in your toolbox, as none will give you everything (e.g, insurance is required and it will cover you for many situations, but not always; asset protection (LLC) is litigation insurance and complements regular insurance, by minimizing the target and making it unappealing).
2. Asset protection is a form of insurance – insurance against litigation. My recommendation would be to apply the "2% rule" - the cost of setting up and maintaining your asset protection should be less than 2% of equity you are trying to protect. Let's say, it costs you 1.5K to get your structures in place (holding LLC or Series-LLC, with or without land trusts, with or without separate operations LLC) and 0.5K per year (for maintaining the LLC properly, bookkeeping, lawyer and CPA, etc.) for a total of 2K. You should have 100K or more in equity to protect before it makes sense to spend that money - compare that with how much you spend in annual insurance for the same property/equity under the same FEAR principle (False Evidence Appearing Real... or what if's).
3. ABA is more of a subscription service, set up for a maximum gravitational pull - meaning once they capture you in their "orbit" you will be required to pay regularly and more and more for continuation of services. It's far from a one time deal - think timeshare, easy and exciting to get in, hard to get out.
4. If you are new to REI you should be primarily concerned with finding good deals and growing your business first. I would not suggest to look into establishing LLCs and asset protection strategies till you have at least $100-300K in equity (!) and only after you covered properly the "other" aspects of risk management (insurance, umbrella insurance, proper property management, etc.).
Unless you are doing flipping (or AirBnb), in which case I suggest you look into Series-LLC and you operate each flip in its own child-series (if not clear why, ask for more details).
Personally, since AssPro is not cheap, I spent numerous hours researching from multiple sources the whole LLC question and asset protection matter and all the rabbit holes it opens. I gathered all my notes in a 50+ pages document touching on formation and maintenance of LLC and business structures, transferring assets, protection strategies, trusts, anonymity, insurance, levels of protection, etc. including when you should do it, how many properties per LLC, due on sale clause, selecting an attorney, fees, checklists and resource materials + some diagrams to help you in decisional flow.
Doc: https://www.biggerpockets.com/files/user/CosIorg/file/tritoriam-file
Asset Protection Decision Diagram - to help assess the need for asset protection, and what to implement : https://www.biggerpockets.com/files/user/CosIorg/file/asset-protection-decision-diagram
Asset Protection Onion Diagram - what, when and at what cost one should implement in terms of asset protection - https://www.biggerpockets.com/files/user/CosIorg/file/asset-protection-onion-diagram-v2
What is needed for a complete asset protection OR the domains that need to be intersected to find asset protection. - https://www.biggerpockets.com/files/user/CosIorg/file/asset-protection-spectrum-diagram
How a fully implemented asset protection layout might look. - https://www.biggerpockets.com/files/user/CosIorg/file/asset-protection-structures
Let me know if have questions or want to chat further - I can give you my investor perspective.
Thanks
Costin
PS. Read this book first - https://www.amazon.com/Every-Landlords-Property-Protection-Guide/dp/1413307000 - before getting into more complicated and expensive measures of protection.