I haven't looked into the Tige too much but just to throw in a little insight ...
I looked at supra exclusively for the Z5. I feel like it is one of the best options on any boat out there. Provides no hassle shading and the utitily is great. We usually throw a tube up there and it is completely out of the way.
I also like the playpen, althought there is less walkroom, the boat is almost like one giant pillow. The wife is also a huge fan since her favorite place to sit is up front. 3 or 4 girls can sit up there once you lift the seat. She also enjoys laying up there (in the middle) looking back to watch riders. It really is a great space. Plus you can get a lot more ballast in the boat. Comes in real handy on a rough day because you can fill the sac up and the boat rides across the chop much better.
Stereo seems to be a mute point.
Fly high soft bags in the Supra are great because they are easily upgraded, which you will want to do when you start surfing.
As for the looks, i personally like the classic look up the Supra but the new pickleforks do stand out in a crowd.
As others mentioned, great boat either way. Go drive both, is it the same dealer. Where are you located now that i think about it, our Supra dealer just started carrying Tige.
If this is the toughest decision you have to make this summer .. life must be good.