Of the three that you listed the hands down best is the LT-40. It's a trainer design that has been around for a long time and is a great flying plane.

Next would be the Tower Trainer. It's a good trainer at a very affordable price.

The last on my list is the Nexstar. In my opinion it's way over priced. Yes, it's got all the "extras" that you mentioned, but those usually come off before flying. Most instructors will turn off the AFS, and remove the speed brakes and wing droops. These are just gadgets that Hobbice uses to sell more planes. The plane is a better trainer without them as it teaches the student to fly with a crutch to become dependant on. Because these extras usually come off I recommend that students don't waste the extra money.

As far as flying goes the Tower and Nexstar are pretty similar once you get the gadgets off the Nexstar, and both will do a great job teaching the student. But the LT-40 flies better than both of them easily.

If price is the determining factor then go for the Tower Trainer. It's a great trainer for a fantastic price, and then the LT-40. Once again, I don't like the Nexstar because it's over priced.

You'll do fine with any of the three, so you'll have to decide which one you want to get.

Hope this helps

Ken