Yes, I think the Suns are a championship quality team. They lost several games against top teams in the league (they lost to the Lakers, Spurs, Mavs, Jazz 2x, and Clippers. And don't forget, they took the Jazz and the Spurs to OT in those losses). However, it was about two games before their last (and only) loss (against Utah in OT by 3) that before Stoudamire really began to click and get back into his form.
I think the Suns have what they need to be a top team -- and I think they will challenge any team in the league. Their schedule is pretty easy right now -- but you can't really hold that against them. If they can stay healthy, we will get a chance to see what they are made of in Feb when they play the Spurs and Utah.