Gratz on the new bike and the desire to ride. It's fun.

I ordered my road bike with the computer so it was all done for me when I arrived to get fitted. I do have cadence and I check it on occasion when I ride. Not sure I can do 90, but I generally am in the 75 - 80 range. For me, I like to see mph, distance traveled and my computer comes with time and temp. I can easily press a button to change to cadence, heart rate, Alt, what time my breakfast is ready, etc. At the end of the day, you have to decide what it is you'd like to see on your computer.