I'll agree that an Ugly Stick (or one of its derivatives) is the way to go. They can be as slow as a trainer, are much better in the wind, take off and land easier than a trainer, and will let you start working on aerobatics. The difference in flight is that the stick doesn't self-correct. So when you roll into a turn, the stick doesn't resist the roll and try to level itself; it just does what you tell it to. I would compare going from a trainer to a Stick as a similar experience to taking the training wheels off of your bicycle when you are learning to ride it. You actually find that it's easier to fly without the self-correction and more fun too. Of course, if you are still depending on the plane to be self correcting a Stick may be too much for you, but if you feel like you are in control of the Apprentice for your whole fight then a second trainer is probably a waste.
Out of your list though, I love the Avistar. I really wish they had left it alone because the flaps aren't needed for a beginner, but the plane is still nice and stable and better in the wind than a traditional flat bottomed wing trainer. Lots of guys turn their Avistars into their fun planes later with hotter throws and a rearward CG. The flaps let you fly off of water easily if you choose to do that later, and the aerobatic capabilities aren't too shabby. One of our hot shot IMAC guys in the club likes to take his Avistar out and do rolling circles and inverted passes a foot off the ground for the students on training night, so the plane can take it.