I've had Defenders in the past. Currently have an Armor on my 5. That'll help transition me to the 6+. My 5 w/ Armor is the same width as the 6+ (without a case) and about 1/2 inch shorter.
Decided to try the Spigen Tough Armor w/ a glass screen protector this time around. Good reviews and it sounds like less bulk and similar protection (to the Defender).