I used DU travel for my DLR visit (2022). I am not using DU for my upcoming WDW visit (2024).
My agent promptly replied when I asked a question and also let me know when she was not available and away from her desk. She was also professional in her replies and never rude.
But, unfortunately, my agent gave me incorrect advice about advanced purchases for our vacation (her excuse was that she assumed I was visiting WDW and didn't check our reservation to re-educate herself that I was visiting DLR) and I had to ask my agent to apply a DLR discount that I was eligible to receive. I was left with the impression my agent was either unaware of the discount or the dates of my travel.
I was left wanting more from my agent and DU and felt like I can plan my own vacation better than the agent could plan it. I hope you (and others) have a better experience with DU than I had.