Let me add a few thoughts of my own since you asked.
This is a great camera lens combo with the SWP44. I mean top notch. I too shot with the PD150 for years and there are still days I look at that footage and I am amazed at what a camera that was and is.
The Gates housing and my EX1 is in the water with me shooting tv. 13-16 locations a year, 15 days a month, up to 5 dives a day, in and out of the housing, tossed, carried, and abused, much to my chagrin, by lots of customs, immigration, inspectors, boat handlers, divemasters...you name it. It has held up and when I messed something up. Gates was right there sending me whatever piece I managed to knock off or screw up. I have nothing but praise. The most common issue I have is knocking off the little control rubber ends from being in a hurry to insert or remove my camera. Now Gates just ships a bunch of replacemnts with the housings for impatient people like me.
I carry my housing in a backpack on the plane. Amazingly, with the flat port on, the housing will fit under any airline seat. I also, against many peoples advice, I always keep the camera in the housing while traveling without ever an issue. I keep the monitor, handles, lights, battery, charger, and nexto recorder in the small carryon. In other words, I travel with everything I need to shoot into the cabin with me.
Im going to give you some of the harder lessons:
Since you are moving from a PD150 to the EX1 as I did...here were the big adjustments for me.
1. The minimum focal distance of the camera combined with the standard port make this a real bear in the water.To get the kind of close shots you would normally have gotten with ease from your PD150 will require diopters and a very steady hand. You just can't get inches from the subject like you could with the PD150. So as others have said, the SWP44 is a must for bringing the minimum focal distance under control.
2. Even shooting with the achromat diopter and the flat port, you need to get the camera further back then you would be used to and then zoom in to your subject. So junk in the water gets a little frustrating but the results are pin sharp minus the atmospherics. I really like this combo but it'll cost you another 1K. It just isn't anything like the PD150.
3. It is infinitly frustrating not to have zoom focus, histogram, zebra, peaking, etc not displayed through the external monitor. This is Sony's doing and nothing to do with Gates fine design. But now with the nano, you have to have it off anyway. BTW...the nano fits in the EX1 housing no problem.
4. The matrix on the camera is very powerful. Learn about it and get some profiles saved. I keep a card with 5 land profiles and a card with 5 underwater profiles. When you get it dialed in. WOW!
5. I switch between manual focus and auto focus all the time especially with the 44c and I want to be certain I dont hunt. Getting your fingers in there with dry gloves or 6mm can be tough. I put a little cclamp on my control when doing full dry so it is easy to change. It also lets me easily identify the knob.
6. The camera will whitebalance quite deep without the red filter. However, don't do it. Use the filter anything more then 15 feet. Add 3db gain to compensate and, in the end, you will be happier with the results. If you want to shoot at zero db, then you will need to work with the matrix.
7. The camera, out of the box, appears noisy underwater. The full auto mode of the camera increases gain upto 18db. You need to learn this camera and shoot it in manual exposure mode for best results. Leave the AF on but drive the rest. This means calibrating your 43 monitor as best you can and then using zebra and histo in the viewfinder until you get a feel for what the camera is recording and what the 43 monitor is capable of showing you.
8. It's a manual housing! With that bullet proof design comes a little care a feeding of the seals and mechanics. Make sure your seals are snug and you always inspect your housing after travel. Gates recommends dry diving the housing each trip before loading the camera. I don't but should. Sinking that bad boy empty is quite the challenge.
I've told you these things so you can be better prepared. This is a serious rig and yields quite impressive results. Pro results. The 44c is very forgiving. Very! So getting it is a must. I too was an early adopter of the Gates EX1 housing and they have listened and constantly made improvements to the design. Others have already mentioned some of them. The housing is just so nice in the water. Put two 8 ounce weight on the left side of the housing and one 4 on the right and BINGO! neutral balanced housing.
Feel free to ask anything else.
Mark