I also trusted Coinex, MintPal and Allcrypt, so.... my record is not very good. Every exchange is a risk, just by virtue of being an exchange.
I like Shapeshift because I only have to trust them for about 1 minute.
I too have trusted those, but i put a time limit on how long they should be trusted. The longer an exchange is active, the more prone it is to hacking and such. It should become stronger over time as well as they can fix the potential security flaws, but eh. That honey pot sweetens as it grows and crimes of opportunity become more appealing. It becomes a bigger target. Similar concept to "too large to fail" but i think society needs to develop a formula for corruption. Sorta like a half-life on altruism. Things generally start off with the best of intentions but over time the locusts take note and swarm. The locusts are people who stop at nothing to obtain what they want for them selves while using the backs of others to reach their destination. Most americans, not their fault really, how we were raised.
I am still prepping my self for the day cryptsy and btc-e and poloniex go poof. It isn't a matter of if, just when, imo. Running that fine line of how many coins i wanna keep on the books at any given day to mitigate my loses when it does take place. If only there was something like a classifieds page or a craigs list where people could make offers of buying and selling but those coins weren't stored in a centralized locale.. oh wait .