They are noticeably heavier than a regular chain, despite their effort to try to lighten them with hollow pins, hollow plates, they still weigh a ton.

I used to have a Gusset half link chain on my BMX but never on my fixed gear that chain stretched and wore a lot quicker than a regular chain, however, this is because BMX drive trains are a lot smaller than a fixed gear...23/9 vs 44/17 etc etc. I've yet to put a half link chain on my fixed gear though, if you do I would recommend using Interlock V2...they are tough as hell.