No, I would not!  If for no other reason then because every time their site is down for a few hours - or worse misbehave because the backend is down, I get worried that they have been hacked.  They haven't, of course, and even if they had it would be *very* difficult to run with my coins because of the double encryption - but perhaps they could manage somehow to poison the javascript and get the password.  Anyway, I happily use blockchain.info for everyday bitcoining, but would suffer a nervous breakdown every time the site was down if I had that kind of money in it    For that, I recommend an offline wallet, for example Armory.