Elementary OS 5.0 dual boot with Ubuntu 18.04.3 LTS?

I just got my first Linux computer which came loaded with Ubuntu 18.04.3 LTS. I don't like it. I had them load Elementary Juno (5.0) onto a USB drive for me because I had already decided it was probably what I wanted anyway. I am installing Elementary and it's asking if I want to dual boot with Linux or wipe it out completely. What I want to know is if there is any advantage to my keeping Ubuntu as a dual boot or should I just wipe it out? If I dual boot it I can change the allotment of memory but it says that it can't be undone. If I do dual boot should I allot Ubuntu less or keep them pretty even? Thanks, in advance, for any help with this. I have Googled it but I'm a little out of my league right now.