I support your advice to IAMEpic2004 but from my experience I'd say go directly with the Dayan. It's weird that some people (including myself) finds a problem with internal catching in all Moyu 2x2s (I have a LingPo but I have heard the same about YuPo and TangPo) while others can use them as mains. In my case catching can ruin at least 1 in 3 solves so I cannot seriously use it. In any case, if finally going for a Moyu I agree that at least the YuPo is basically the same but much, much cheaper.
That will never happen with the Dayan. The only problem is that newer Dayans have a different plastic and are not as good as old ones (that's what I've heard, in any case). It happens to mine

It's a little less smooth and more bumpy that old ones.
I agree that Hualong is good enough. I have the TangLong and, at best, it's marginally better. I'm almost a collector of 3x3s that's why I keep getting new cubes that don't make me any faster. I'm also waiting to get my hands on a YueXiao
Cannot agree more!!!
No idea, as I don't do 7x7... yet. But if he's not sure about getting into 7x7 I'd also get a Mini SS. The Cubic AoFu is a bit expensive.