I can't speak of the Quarab crosses, since I've never owned/ridden one, but here is Marq My Words, a pure bred 7 y.o. Arab stallion that I gelded. 2 months after he was gelded, I rode him in a Christmas parade, green broke (supposedly) and the following month I rode him on the New Year's Day trail ride. I then sold him to a little girl who had been bought the 'perfect' beginner horse that scared her so bad she wouldn't go near it.
Here's the ad I wrote about Marq:
Marq My Words by Nokitov (*Muscat x *Nahodka who was by Arax x Nepriadwa) out of Vallejo Marquessa (Tornado x AM Silversparrow who was by *Silver Vanity x *Blue Millet)
Marq is a 7 yo gelding, started by Eddie Ralston and now being ridden in Parades and on Trail rides and through Neighbourhoods by me. Marq is the most level headed, loving, gorgeous, smart, brave horse ever. My first ride on him was in a Christmas Parade and he was wearing an unbelievable collection of noisy bells, glitter, garland, ornaments.....you name it, he had some. Nothing phased him, not even the helicopter that flew very low overhead.
His 2nd ride was on Jan 1st, right after I had injured my shoulder. I hopped on, told him "Try not to kill me." and off we went. It was wonderful!
I just recently rode him through the neighbourhood at a friend's house to get to the trail we wanted to go on.. All the little kids came up, dragging rakes, bouncing basketballs, driving their Malibu Barbie Jeep, I thought I was going to die right then. He never even blinked. I should have known better. It was the first ride for either of us in 5 months.
Depending on the horse, I would PREFER an Arabian to any other breed for a beginner. The key is THE HORSE, not the breed.