Congrats. You will enjoy the Kickr.
I recommend mixing it up and using ERG mode sometimes and level mode sometimes when doing tempo, sweet spot, threshold and longer VO2max intervals. For short duration intervals of 1 minute or less, level mode is best.
ERG and level mode have pros and cons. If you use both, you can take advantage of the benefits of both styles and be a more adaptable athlete.
Here is a run down on the advantages of either mode.
Coach Lynda