We've owned in Mexico (Baja) for 10 years now. The reason for the trust ownership goes back to an old law for defending the coasts and borders of the country. If you aren't buying on the coast, you can, in fact, own directly.
The trust was the Mexican way to get around the law without changing the constitution. The trust is authorized to act only on your orders and only in your behalf. They are for 50 years and can be renewed. At first I thought that was a drawback; then I realized how old my children will be in 50 years--and the earliest trusts, which were for less time, maybe 25 years, have, in fact been renewed as they have expired.
The Mexicans laugh at Americans and title insurance. It has been available in Mexico for only a very short time. The reasons they didn't use title insurance are quite logical when you understand the system that was in place.
1. It is the notario's job to certify that the title to the land is free and clear. If it is not, the purchase cannot go through. The notario is a very skilled land attorney and it is a position of great trust and responsibility. Where we are in Rosarito Beach, they were very proud when they got their own notario.
2. Until recently, almost all purchases in Mexico were cash, paid in full (financing was exhorbitant and was for only 7 years). When the offer was made on a property, a small amount was paid down, and on the day of the sale, all parties meet with the notario. He certifies the title as free and clear and records the details of the transaction to be filed in Mexico City. The money then changes hands; everything is done at the same time. Then the trust can be completed and registered in Mexico City.
3. American title companies are not, in fact, licensed in Mexico; they work in an "advisory capacity" only. They do not certify property that a notario has not certified; therefore, there is no risk to them (or the buyer). Basically, they duplicate what the notario does by coming along after him and saying the title insurance will operate in this purchase. I've known of buildings of condos in our area where buyers could not get title insurance; that's because the company already knew the notario had refused to certify units in the building.
If buying from an American, the American should have a trust; if he does not (and many don't because they simply didn't bother to get one), the land may not, in fact, have a clear title. A Mexican national can own the land without a trust, of course, but he should have a title document from the notario showing clear title.
In the U.S., no one would even consider buying land without clear title; for some peculiar reason, as soon as Americans go south of the border, buying land/house/condo and assuming there is a clear title seems to be o.k.
As to buying in an unfinished project.....the rule of thumb is "buy what you see." If you like it enough, as it is, to buy, that's great. If the promises never materialize, and you still like it, that's fine. If you won't be happy if the amenities aren't all actually there, wait until you see them. I have two sets of friends who have been waiting for nearly 5 years for "their" buildings to be finished.
You also need to know that in Mexico, it is typical for the developer to build with your money. It is not held in escrow. You pay whatever the first payment is and the project begins; you pay more, and it continues, etc. If the developer goes broke, you will have a problem because the money you supplied has been used to get the building to whatever stage it is in at the time. If he goes broke, there will be leins against the property, and those will have to be paid before anyone considers your rights to the property, your funds, etc.
We are very happy with both our properties in Mexico, but familiarize yourself with the Mexican laws. They definitely have laws, but they aren't the same as laws in the U.S. Think of yourself as an alien, because you are, and recognize that their system was not set up to comply with what you believe it should be.