The only real weakness is that you can't repair it. It doesn't add a bonus to strength like some PArmor does but it also does not have an agility deduction. It has an AR of 50, highest in the game, but can be outclassed be Tesla armor since you can repair it to full, it is only a few AR less and it adds some modifiers. Ranger Battle Armor is possibly the 2nd best armor depending play style, but it's light, strong(AR44) and has several modifiers. There is also the Winterized T51b from the Operation: Anchorage DLC. The in-game version and the non-playable NPC version got turned around in scripting making the playble near indestructable. I have been playing through 6 levels with the winter version and it has never lost any HP.