I'll leave reviews of various kites to the other active fliers here, but I wanted to address one aspect...
A single kite generally isn't enough to stay successful in competition, particularly the somewhat heavier "beginner" or "intermediate" kites like the Quantum or Hypnotist... As wind conditions vary greatly from competition to competition and day to day, you may want to give consideration to the need for ultralight, standard and vented kite models so you're aptly equipped for whatever the competition day brings.
There's nothing like having only one heavy kite on a light wind day, or only a vented on a light wind day... That's the sole reason I'm not competing in dual line this year or next, because my Kymera is only available as a standard and I need a set of 3 variants to effectively compete.
But also know, many other competitors are generally happy to loan whatever you're missing, even if they're in the same competition as you... Time and time again over the years, I've beaten other people's kites and also been beaten with my own, happily.
Don't let a lack of equipment be a discouraging factor, but it'll be useful to give consideration to what you might need tool-wise.
When I was competing regularly as a solo dual line flier, my kit generally included:
Ultralight
Standard
Mid Vent (on and off)
Vented
120' x 50# lines (UL conditions)
120' x 90# lines (medium wind)
120' x 150# lines (more wind)
120' x 200# lines (high wind)
90' x 90# lines
90 x 150# lines
Longer lines for precision, shorter lines (sometimes) for ballet, changing weight and/or length offers different flight characteristics.
Food for thought, the list above is useful, but certainly not required to be a competitor.