How about neither. Get a noss head. Same thing as the Pro Design only you dont have to take your stock head studs out and put longer Pro Design ones in. The noss head uses the same domes as the Pro Design. 90% of all "cool heads" use the Pro Design style domes. The trinity one has to use trinity domes. So you get to pay the trinity price, plus if you ever need custom domes for say a 4mill stroker crank you will only be able to get them from trinity. I am sure a set of custome domes from trinity are a pretty penny too.
Trinity head also uses some kind of gasket along with some orings I was told. So when you take the head off you will have to get another head gasket from trinity, vs just slaping the noss head back on with the o rings.
Noss is a sponcer on the site too. BHQ members get 10% off. Let him know when you order it, or put BHQ in as a coupon code.
Plus you can get the noss head in anodized colors.
www.nossmachine.com
josh