Not sure what zoom levels you are looking for, but Text_Maker allows custom zooms from 30%-200% as well as text wrap. The only issue is that I find it slow sometimes. Works with keyboard (even shortcuts with Ctrl+C, Ctrl+V, etc work in it).
But go with whatever one suits your needs better. Trials should be the full version of the app to give an honest representation of what you will be getting when you decide to buy the app.
Edit: the general difference between a trial and free version of any app is free versions will either have missing features from its paid app or just remove ads. Trials on the other hand are usually timed trials and offer all the app has to offer to provide the user the experience to make an informed decision. Though in all honesty, that would also depend on the developer. But most trials I've come across are full featured that expire within a set timeframe (ie. there are no missing features in the trial).