Here's the overview:
The Entrada has the same flush engineering as the Eco-Drake 1.28 CST744EL. That flush is effectively the same as the regular Original Drake CST744SL. Because the regular Drake and the Eco-Drake both use exactly the same bowl, which is designed to work on 1.28, you're really not getting anything from the extra water on the "SL" as opposed to the EL. ("S" is 1.6, "E" is 1.28)
The Entrada has a 1000g MAP rating (which measures ability to process volumes of waste). That's just plain awesome. It really doesn't get any better. And Terry's real-world experience is that customers like them. This toilet is positioned to be the new "entry level" ("Entrada", get it?) Toto as far as price goes, and Terry has repeatedly said that it is an exceptional value.
I'm the one that made the comment about the flapper. What that is is Korky's new flapper design, with plastic rather than rubber hooks that attach to the overflow riser's "wings". It gives you the benefits of plastic in certain places and rubber in others. That same flapper is similar in design to Korky/Toto's new "universal" Toto flapper (2023CM at HD), which is made by Korky and available at Home Depot. Now that 3" flappers are standard, you will never have a problem finding an aftermarket flapper that fits. Korky already had a 3" universal flapper that works in any 3"-flush-valve Toto (3060CM at HD), as well as some non-universal flappers that fit many Totos (e.g. 2021CM at HD); this new design is now an "official" Toto part.
The fill valve in there is a version of the Korky 528, which is in my view the best of the 3 different manufacturers' fill valves used by Toto. Years from now, when the moving parts of that valve need to be replaced, you yourself can buy a $4 part (R528) at Home Depot, and change just that part in less than five minutes without taking the valve out of the toilet, and be back in business for years more. It's so easy that Terry often tells customers how to do it over the phone (as will the manufacturer, Korky), saving them the price of a service call. The Korky guts are all Made in the USA (Wisconsin), if that's a consideration for you.
I think that ultimately, the Entrada is going to take a lot of business from the Original Drake, because it's a very-high-quality toilet at a favorable price point. And I think Toto expects that.
A couple of other thoughts: First, both the Drake and the Entrada (and most other modern low-flow toilets) develop head pressure by putting more water in the tank than actually dispensed. Each toilet will only use 1/2 to 1/3 of the amount of water in the tank when flushing; the weight of the extra water helps develop head pressure. All Toto tanks, with their 3" flush valves, are going to provide more-than-adequate pressure to do the job. Second, "pressure" isn't anywhere as significant a factor in a well-designed gravity toilet as is the trapway. Remember that a gravity toilet doesn't "push" the waste from the bowl; it develops a siphon that "pulls" the waste through the trapway and into the home's DWV system (drain, waste, ventilation), which starts at the flange/closet bend in the floor. Toto's trapways are patented, and are the best in the business. They were the first to develop a trapway that works very well on smaller amounts of water, much of which has been attempted to be duplicated, belatedly, by others. Their engineering and production quality (and quality control) is first rate.
I think Terry's advice in another post is the best: in this general price range, you have the Entrada, the Original Drake and the Original Drake with the New Tank (which is not functionally-different, just aesthetically different). CST744ELN for the latter. Just pick the one you like the looks of best, that suits your price considerations, and buy that one. You will be very happy with it.
As to purchasing, be aware of what the street prices on these should be by doing some research (e.g. online). We don't recommend purchasing online for "ethical" reasons and because the arrived-broken rate is so high (which has driven up the prices of online sellers, by the way). You can also look at Terry's prices above, which are fair. Terry's installation charge is the bargain of the century, however, given everything that he gives his customers (new line to the wall, expert installation of Totos with Unifit adapters, which these don't require, etc.).
What I personally recommend, and have received a lot of good feedback for, is the following: decide on the exact model and color that you want. Open the Yellow Pages (remember them?) to the section called Plumbing Supply and pick out at least FIVE nearby sources. Even if they don't advertise Toto, virtually all can get it from their suppliers, and many don't advertise it even if they carry it because they think only plumbers have heard of Toto. Call them and ask what their price would be if you came in today and bought/ordered/paid-for that exact model and color. At least one will be rude. At least one will be nice. At least one will have some stupidly-high price. At least one will have a very good price. And at least one will be nice and have a good price. Then you can decide who you want to do business with. Advantage: when it comes in if it isn't in stock you can look at it with the guy right there in the shop and make sure that it's not cracked or broken. And you have a place nearby to return it to if you discover a problem when you get it home.
Good luck, and come back with any questions!!
The new Korky/Toto universal flapper, available at Home Depot for like $13: