DH and I are long time WDW people too. Last year for the first time we visited Universal. We enjoyed ourselves, and really liked the new experience.
Having said that...
1. Universal is not anything like Disney. Other than they both have rides. When you go you have to keep yourself from trying to compare. I know it's hard, I constantly had to kick DH, but it can be done.
2. Enjoy Universal for what it is. Their colors are vivid and their experience is unique.
3. Be prepared for the differences (it helps to keep you from comparing once you are there!).
4. Keep telling yourself you are not being disloyal to the mouse by enjoying Universal.
Having told you not to compare, let me do a little comparisons for you, these are just my opinions.
Disney has fast pass, if you stay at Universal they have front of the line. Front of the line is GREAT! Much prefer it to fast pass.
Disney and Universal both have shows, both do them very well.
Disney's rides are longer, Universal's are shorter but more intense.
Disney's water rides (Splash Mountain) may get you a little damp, Universal's water rides will get you soaked.
Where ever you are in MK that is the only theme you see, Universal does not follow that and you can see the different lands where ever you are.
Disney CM are GREAT, Universals remind me a bit of the younger sibling who is tired of being compared to someone else. They are good, but it is not the same thing.
You will enjoy your time at Universal if you accept it for what it is. It really is very good given a chance. You will still love Disney though. There is room for both. If you have any questions I'd be happy to answer them if I can for you.
