I use them. They work great as primaries. A couple caveats - if you fill it really full of wort, you should probably use fermcap to keep the krausen in check. In the same scenario, you might consider unscrewing the gas in post and clamping a blowoff tube to it instead of using a disconnect.
I don't have truble (pun!) with lots of trub in the bottom. It usually is a nice yeast cake. Maybe an inch or two. But I do transfer my wort off the cold break/trub after doing a whirlpool in the boilkettle.