Eh, other than maybe stat differences the only thing I've seen on all legendary arms are reload x weapon faster and melee faster/throw grenades farther/melee hits restore grenade energy. Boots are just increase heavy ammo capacity which is nice but I can carry 999 rounds of AE ammo where ever I go lol. I use my primary a lot more often than I do my special so having that quicker reload is nice, plus the stats on my current armor (dead orbit/vanguard/crucible) refresh my grenade and super quickly enough. For the play style I like, being 29 is better than going for 30 and possibly having to change my load out.