The apprentice is 14" wider and 10-15 oz heavier. Even with the bigger motor it might not be faster or "more powerful". I would buy the T-28. They fly great stock, and most hobby shops can get parts faster. Two of the LHS I go to stock most the parts on the wall.

Plus, when you get tired of the stock T-28, just add a E-flite power 15 or 25 and a APC 11X7-E and it will fly like a newer/faster plane.