I too use the hugy, and over all love it. The Hugycheck system is definitely the best there is at is the only housing on the market that you can be sure is not going to leak before you get in the water. You can get leak detectors for many but for me i think that is a bit like shutting the stable door after the horse has already left.
The downsides as eefella said, no tripod mounting hole... and if you get the standard port there is no manual focus for the macro. You can indeed get the Inon magnetic one and i hope to buy one soon, just money stand in the way.
I also find it a lot more ergonomic than the others, and with the strap it is easy to to shots with one hand.
The standard viewfinder leaves a little bit to be desired and you can change it for the inon ones though you are then limited to 75m.
When you look at the cost or them against the others for me it was the clear winner and have been very happy with mine. You might want to think about getting a different wide angle dome but i use the hugy one, though i mainly do macro so can't really comment with them. I have got the TTL converter in mine, though was never really pleased with the results as you have to have the strobes pointing straight at the subject for it to meter properly and so i just use mine in manual now. (i use the inon z240 mkIVs).