This looks very cool. How does it compare to the URPRO filters that ikelite sells? I've got one and never tried it - just always used strobe..
If you have a P&S that allows manual WB, are you better off using something else, than the auto magic filter?
The UR Pro filter is very nice - I used them regularly before I invented my own filter. Please note that I design my own filters and while this reply is what I believe - you may want to account for any bias.
The UR Pro filter was designed before the days of digital cameras. As far as I know it was designed as a perfect filter to counteract light absorption through water at a specific depth. I have found that if you are not at this depth (between 7 and 9 m deep) then you need to set the WB manually to get a good results. The UR Pro filters are either glass or resin - and can be mounted outside your housing - and removed and replaced during a dive.
If you got a UR Pro filter with your Ikelite housing - I would recommend trying that before looking at buying other filters.
I designed the Magic filters with a different philosophy. They were designed specifically for digital cameras - by filtering unuderwater light so it is in the range that the camera's electronics can deal with. With the original Magic this requires manual WB - but works over a depth range from the surface to 15m or more. The Auto Magic is different and here the filter adjusts the underwater light into a range that works with the Auto-WB on your camera.
Magic Filters are optical quality photographic gel filters. They are waterproof - but are designed to be mounted on the lens of your camera for the whole dive.
Regarding the two Magic Filters - if your camera has Manual WB and you will be bothered to set it during the dive - I recommend using the original Magic filter. If you want to take it easy and not bother with Auto-WB then use the Auto Magic.
Alex