I have a rio gold and a rio LT in a 5wt, using a st.croix legend elite fly rod. After a solid 2 years of experimenting with these 2 lines, there's no doubt in my mind that the rio LT is absolutely PERFECT for dry fly presentations. It just seems to float in the air for a split second longer than the rio gold, and it ever so gently kisses the water when you throw it out there. The rio gold is a nice all around line, throwing streamers, nymph rigs, and drys as well. But the LT just seems to do a bit better in a "spooky fish" way. They both cast a mile, and are very slick. The LT is also really good at performing singlehanded spey casts and roll casts. I've never used any manufacturer other than rio, so you can take my recommendation with a grain of salt
Good luck!