I use them exclusively with great success; you can ferment under pressure (there is a thread on here "how to") or do like already mentioned and rig up an airlock to a piece of tubing off of one of your ball lock disconnects.
I have a batch of ordinary bitters fermenting right now, and I got 4.75g into the fermenter. I normally shoot for 4.25-4.5g batches, but got a bit higher efficiency than expected.
When I have this large a batch I use fermcap-s and have yet to experience any problems (this latest batch my latest testament).
My dip tubes are not bent or cut-- I use them as is. I get hardly any sediment/trub when I transfer (under pressure) to my serving keg. However I do a long cold crash, which really helps to compact the trub.
There are a few really good threads on this on here... check at the bottom of the page to "related links".
Good luck. I highly recommend using them in this way; I strongly believe in having multi-use over single use pieces of equipment. Multi-use, ferment under pressure if desired, transfer under pressure, stainless steel, cost is comparable to better bottles (I got mine cheaper).
Only downside, is you cannot see inside. That is it.