Yeah, personally I like the fifth legacy emblem better and you can get the feeling of completion. As far as rewards, there aren't very many, not worth legacying over in themselves. But I wanted to legacy so I could continue to level up. That's really the only reason I think you should legacy. I'd buy as many character items as you can/want because they'll be more expensive the next time around.
If you play as a lone wolf, don't legacy. Being a 75 5th legacy is the worst thing that can happen to you as a lone wolf.
But if you play in a party a lot and enjoy to do everything all over again, go ahead and do it.