It's heavy with my 5DM2 + Len. My arm became muscular after playing for sometime.
However, with fine settings, it works like a charm. I think it might be the most value for money video stabliser of that range you can get, compared to Steadicam, glidecam etc.
No regrets getting it to play video on my DSLR.
But if you gotta go pro, i will still suggest you getting the full set vest + arm + stabliser, either steadicam or glidecam range.