I feel like I've read that some of the double ply gear will kick your ass while getting used to it.
This is a quote from someone on another board about the Metal Ace:
"Metal Ace- prolly the most popular of the poly suits. The support of this suit is also insane, it gives pop and stop. Same as the briefs, if a lifter is not perfect with their technique this suit will dominate you and toss you forward. It will take a good bit of strength to handle this suit if sized properly. A bonus for this suit and all of the Metal gear is you can get it in a week or less. You must be able to force your knees out hard with this suit. A couple of common things people need to adjust on the suit are the length of the legs, if you have a shorter than average upper leg the length of the suit leg will be too long and you will need to have it shortened by 1-2 inches. The second is the thickness of the straps, they are very thick so if your upper back is not of decent size you will have a hard time feeling the bar. This is a personal preference thing, some people freak out if they can't feel the bar and others it does not bother. I always say get a bigger upper back I have not mastered my Ace suit yet and have only used it for a few sessions, so far so good."