Has someone used or is using those soft car roof rack? Are they any good or safe to use?

Yea agree with that, depends on how far you are going I guess. Ive had three boards on mine at 120kph. Didnt move. One windsurf board should be ok tho.

Thank for the advice.... My prob is the ruling dictator of my household wine about me spending too much on toys............ So I am on a tight budget
I could get a pair of those for $50-00 against a $350-00 pair of bars that would fit the rail on my car. I will not travel long distance; just take my gear to the beach or to the office (in town) for a quick sail after work. My board is about 9 kg!

Don't get them, they suck!
I got the "Malone HandiRack" that is the most voted on Amazon.com. It sucks, here in Bermuda you get easily over 30 C and the sun burn (of course not like in Australia but it still burns ... ) and after 1 day of usage the glue of the internal camera took apart and the roof rack was not usable again. My father helped me to fix it and it broke again after a couple of days...
Buy an hard one, I have a Yakima (2 years) and I carry whatever on it, we also carried a huge bookshelf and never had a problem. Simply love it!