As far as Oly vs Ikelite housing goes, this is my take,
Ikelite would be more suitable if:
1) if you have big hands and wear thick gloves, Ikelite buttons are bigger, easier to get around in thick gloves (this is relative, other people seem to do fine with Oly housing as well).
2) stay put buttons when you need to push a button with left hand and use the right hand tto roate the jog dial, with Ikelite, it is easier than the Oly housing where you will have to press the button and rotate the jog dial simutaneously (people manage this ok on PT-015 but Ikelite does make it easier).
3) Ikelite O-ring system is easier to clean and seems a bit more flood proof (this is my pesonal perception, no hard data to back me up) to me but the Oly double o-ring system is not bad either. However there have been quite a few reports of leak on the shutter/jog dial buttons after repetitive use with the Oly housing. However this happens in the minority of Oly housing owners and not the majority.
4) Ikelite has not made an official announcement yet but they have decoded TTL code for Olympus housing so if you use Ikelite housing with Ikelite strobe, you can get TTL (this is true of the Oly 5060 and they are pondering the same option for 5050-hopefully they will do it as there are many more 5050 owners right now than 5060 and it seems that many divers are more skeptical of the 5060 anyway).
However one definite advantage of the Oly housing is that if you use Oly housing, especially with Inon strobe, it is a much more compact system than Ikelite housing with Ikelite strobe.
Someone is also making some wireless sensor thing for true TTL control for PT-015 housing with Sea and Sea strobe but I don't know too much about it.
Personally I own an Ikelite housing and I am very please with it.
I apologize for any typo, had a beer or two too many tonight so I can't seem to type very well
