Seen them, and they've been recommended on other 'corny fermentation' threads before (thanks though Michael!). As posted, you can remove poppet and spring/pin assembly for more through put, or if you have a bigger hose (I forget diameter), you can just remove the post and shove it on. The only concern is VIOLENT ferments, and wort that is dry hopped or has a lot of hops/trub in it.
The strip for the temp is fairly accurate, but the center of your wort during fermentation will be a couple degrees higher. Those darn yeasties just love going to town and create a lovely exothermic reaction, what can I say?
As far as under pressure, I don't bother with pressurizing the lid for primary. The fermentation process is going to create a nice blanket of CO2 over your wort, and will have excess (which is what will come out the airlock/blowoff). I did originally invest in a drilled out corny lid, that I used a drilled stopper and an S air lock. Used it once, and now stick with a blow off tube exclusively (rather safe then sorry). The nice thing with cornies though, is even if it gets clogged, it's not going to blow the lid off, or create over 130 PSI before I notice (max pressure on cornie according to all the imprinted ratings I've seen on them).
Hope this helps/makes sense... Still getting over a cold, but this winter warmer certainly is good....