i still use a hc9 underwater.
Yes focus problem would be for any camera, It important having the abilty to fix-focus for low contrast scenes such as low water visablity. but auto focus is not a problem other then that. When given a button on the housing the photo button will get you a still camera at the same time as video. (even while in video standby) The Flash on the camera helps stills. But is partially trapped inthe housing. Can even be synced to an external sttl strobe given flat window housing. I use a on camera wide angle full time. Tape gives mpeg2, which edits fines in a modern editor. tapes are still inexpensive about 1/3 of flash (per bit?). Tapes are immeadatly archiveable by putting full ones on the shelf. The time of tape cameras is ending at this time. (as a new product purchase) I have read that cx550 (flashmemory) is a worther camera (2 years newer ) with better lower light and built in wide angle. Power on tape startup 8 seconds, i guess , is slower then a flash camera? so some shots could be lost. Power on standby the heads are spining lightly on the tape in the same spot and if waiting in standby alot can get the heads dirty.
Answer to post> HC9 is worth going to HD at the right price, it must be a discount as when as comparing to CX550.