how heavy are these? are these comparable to cartels in weight and stiffness, response?

They are very comparable to the Cartels in a lot of aspects. They are about a 6 on the stiffness scale and the response is good on these. The only problem that I've come across is that the bolts from anywhere on the binding will come loose really quickly. My buddy lost his strap first run of the day and a bolt on the heel cup attaching the highback came out. Make sure that if you pick these up to lock-tight the shit outta them. I love Rome, but only their decks(I ride a 154w Machine). Personally I have a pair of '10 Union Contacts and couldn't be happier with them. Anything in the Union line is sick. They are totally bombproof and never give out. Or try the Forces or Datas from Union. Trust me, if you get a pair you will not, by ANY means, be dissapointed. Hope this helps :)